Trustworthy statement is literally a faithful (pistos) word (lógos here used to indicate a concept or thought). The Greek order of words is, “Faithful is the saying” or "Trustworthy is the word"  This specific phrase is used five times (click) in the Pastoral Epistles but nowhere else in the NT. 

Hiebert feels this saying is a...

motive for suffering for Christ's cause, Paul holds up the certainty of the relation between our conduct here and our future condition." (D. Edmond Hiebert. 2 Timothy).

Paul seems to use this phrase to introduce a truth that was axiomatic, a truism in the early church that was commonly known and believed. The formula serves to place Paul’s stamp of approval on the content of the quotation.

In Morning and Evening Spurgeon has the following devotional note on "the faithful saying"...

It is a faithful saying.” — 2 Timothy 2:11 Paul has four of these “faithful sayings.” The first occurs in 1 Timothy 1:15, “This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners.” The next is in 1 Timothy 4:8, “Godliness is profitable unto all things, having the promise of the life that now is, and of that which is to come. This is a faithful saying, and worthy of all acceptation.” The third is in 2 Timothy 2:12, “It is a faithful saying—If we suffer with him we shall also reign with him”; and the fourth is in Titus 3:8, “This is a faithful saying, that they which have believed in God might be careful to maintain good works.” We may trace a connection between these faithful sayings. The first one lays the foundation of our eternal salvation in the free grace of God, as shown to us in the mission of the great Redeemer. The next affirms the double blessedness which we obtain through this salvation—the blessings of the upper and nether springs—of time and of eternity. The third shows one of the duties to which the chosen people are called; we are ordained to suffer for Christ with the promise that “if we suffer, we shall also reign with him.” The last sets forth the active form of Christian service, bidding us diligently to maintain good works. Thus we have the root of salvation in free grace; next, the privileges of that salvation in the life which now is, and in that which is to come; and we have also the two great branches of suffering with Christ and serving with Christ, loaded with the fruits of the Spirit. Treasure up these faithful sayings. Let them be the guides of our life, our comfort, and our instruction. The apostle of the Gentiles proved them to be faithful, they are faithful still, not one word shall fall to the ground; they are worthy of all acceptation, let us accept them now, and prove their faithfulness. Let these four faithful sayings be written on the four corners of my house.

FOR IF WE DIED WITH HIM : ei gar sunapethanomen (1PAAI): (Ro 6:3 6:4-5 6:6-7 6:8-10 6:11 Col 2:12 3:3 2:20)

If (ei) All 4 of the "if" conditions (the first two positive, the second two negative) in this "trustworthy statement" are in the first class condition (see notes on Conditional Clauses), which means that they are all assumed to be true or  fulfilled conditions and can thus be accurately translated with "since" or "in view of the fact" in lieu of "if". Thus one could render this passage as 

"since we died with Him" or "in view of the fact that we died with Him.”

Died with (4880) (sunapothnesko from sún = together + apothnesko = to die) refers to a believer's real dying (spiritually) with Christ.

Aorist tense points to a definite event and could point to the past or alternatively could be timeless, the time being determined by the context. In this verse, although the natural reading suggests a past tense event, one cannot be absolutely dogmatic. If could be a death that has already occurred but it could also refer to a death that is yet to transpire. If it is a past tense event, the death referred to is a spiritual death or alternatively if future, it would refer to a physical death, such a martyr's death, as Paul knew he was soon to experience.

When did we die with Him in the past? In a spiritual sense every believer has died with Christ to the power of sin and self as summarized most completely in Romans 6 (Ro 6:3 6:4-5 6:6-7 6:8-10 6:11). In view of the historical context, in which suffering and persecution for the gospel are clearly a major theme in 2 Timothy, it is also possible that Paul may have had physical death and specifically martyrdom in mind (cf note Php1:21). I favor the former interpretation for how else can one truly "endure" unless he has died and been raised to walk in newness of life (see note Ro 6:4).

Because we now live in union with "Christ Who is our Life" (Colossians 3:3), we have the potential empowerment to be strong in the grace that is in Christ Jesus and so to endure whatever suffering our living for the gospel may bring. And so the two ideas (identification with the substitutionary death of Christ or a reference to martyrdom) are intertwined, for the one who has "died with Him" is one who will henceforth live a life that may in fact end in martyrdom, for "all who desire to live godly in Christ Jesus will be persecuted." (2Ti3:12)

THE FOLLOWING FAVOR THIS DEATH AS A REFERENCE TO SPIRITUAL DEATH:

Expositor's Bible Commentary feels that since "we died with Him" is explained...

"in Romans 6:3-6. It is only as we die with Christ, by identification with Him in His death, that we can have spiritual life in Him...Right here and now we are to count ourselves "dead to sin but alive to God in Christ Jesus." The Pauline formula is "You have to die to live." (Expositor's Bible Commentary)

Morris writes that "if we died with Him"...

"This particular saying reminds us of the great truth that Christ died for us and rose again, so that we can identify with Him by faith and receive eternal life (Romans 6:4-10; Galatians 2:20). (Defender's Study Bible)

The Bible Knowledge Commentary is fairly dogmatic stating that "if we died with Him"

"expresses the idea so powerfully portrayed in the rite of baptism and explained in Romans 6:2-23. The reference is not to martyrdom for Christ, but rather to a believer’s mystical identification with the death and life of Christ (cf. Col. 3:3). (Walvoord, J. F., Zuck, R. B. The Bible knowledge commentary. Wheaton, IL: Victor Books.

The UBS Handbook Series notes that...

The verb here is in the aorist tense, indicating that a definite completed past event is being referred to. Since we are actually alive, this argues against interpreting death here in a physical sense, which some interpreters have suggested. It is more likely that death here is used in a figurative sense, referring to the death of the old self when one comes to trust in Christ Jesus. (Arichea, D. C., & Hatton, H.  A Handbook on Paul's Letters to Timothy and to Titus. Page 202. New York: United Bible Societies)

The Evangelical Commentary on the Bible writes that...

The “if” part of the first statement (v. 11) speaks of a past event (“died”) in which we, in union with Christ, died to sin (Ro 6:2–7). As a result of that death, “we will also live [here and now] with him,” that is, in the power of his resurrection life (see again Rom. 6:4, 8, 11). (Elwell, W. A.  Vol. 3: Evangelical commentary on the Bible. Grand Rapids, Mich.: Baker Book House)

W E Vine comments that...

this condition being fulfilled in the case of every believer, for all have died with Christ, the result is assured to all. This identification with Christ in His death takes place at conversion, for in the new birth we pass from death into life; we are crucified with Him and we become eternally identified with Him in His life. (Vine, W. . Collected writings of W. E. Vine. Nashville: Thomas Nelson)

Dwight Edwards writes that..

The death in view here is probably not physical death, but the death of our old man as, described in Romans 6:1-5. And the great promise here is the absolute guarantee of forever living "with Him." It is of no small significance that the first motivation given Timothy here is that of complete assurance in his eternal destiny. This assurance is the foundation for all spiritual service since it determines the real motive for our service. We serve the Lord not to gain heaven; but we serve Him because we are already guaranteed heaven. (Eph. 2:8,9; Jn 5:24)

Focus on the Bible concludes that "died with Him"

points to the Christian’s spiritual union with Jesus Christ in his death and resurrection (Rom. 6:3–10). The Christian has become a new person (2 Cor. 5:17). He has died with Christ once for all to the ruling power of sin and self in his moral nature, and has risen once and for all with Christ to a new life in the practice of righteousness (2 Cor. 5:14f.). Dying with Christ guarantees living with him now and hereafter. (Milne, D. J.. Focus on the Bible: 1 Timothy, 2 Timothy and Titus)

The Nelson Study Bible writes that...

Believers are united with Christ in His death and resurrection (Ro 6:8), which became our death to sin and our resurrection to eternal life. (Radmacher, E. D., Allen, R. B., & House, H. W. The Nelson Study Bible : New King James Version. Nashville: T. Nelson Publishers)

Kenneth Wuest comments that...

The “if” in the Greek text is the particle of a fulfilled condition. Here is no hypothetical case, “if we be” (a.v.), but an, “in view of the fact that we died with Him,” the aorist speaking of a past fact, not a present condition. Paul refers to the same thing in Romans 6:1–10, where he speaks of the believer’s identification with Christ in His death and resurrection when He died on the Cross and was raised from the dead. The words, “We shall live with Him,” are in a context in which they are also found in Romans 6:8, “We shall live by means of Him.” He is our life." They should so be rendered here. We have the preposition sun with the instrumental case. The reference is to this present life as well as the life to come. (Wuest, K. S. Wuest's word studies from the Greek New Testament : Grand Rapids: Eerdmans)

NIV Study Bible notes that...

The Greek grammatical construction here assumes that we died with Christ in the past, when he died for us on the cross. We are therefore assured that we will also live with him eternally.

J Vernon McGee asks...

When did we die with Him? When He died over nineteen hundred years ago. When we come to Christ and receive Him as our Savior, His death becomes our death. We are identified with Him and are raised with Him in newness of life. This means that this very day He wants to live His life out through us by the power of the Holy Spirit. (McGee, J. V. Thru the Bible commentary. Vol. 5, Page 466. Nashville: Thomas Nelson)

The Wycliffe Bible Commentary writes that...

Our justification and forgiveness is a death to sin and the curse of the Law. Live with him looks to the ultimate goal-eternal life, while including our present walk. (Pfeiffer, C. F., & Harrison, E. F The Wycliffe Bible Commentary : New Testament Chicago: Moody Press)

The New American Commentary notes that...

The Greek construction in this context suggests a definite past event such as the conversion and baptism of a Christian (Col 2:12). Paul presented Christian conversion as a dying and rising with Christ. The type of commitment demonstrated in baptism would prepare a believer for the expression of his obedience as a martyr, but the primary reference is to death to self and not merely to martyrdom. (Lea, T. D., & Griffin, H. P. Vol. 34: 1, 2 Timothy, Titus. The New American Commentary Page 209. Nashville: Broadman & Holman Publishers)

Life Application Bible commentary observes that...

The first couplet of this hymn contrasts death and life—the believer’s death to sin at the moment of salvation and the new life begun now with Christ in the world and in eternity. This phrase echoes Paul’s words in Romans 6:8. The entire passage in Romans 6:2–23 describes how believers are freed from the power of sin...Paul could confidently “endure everything for the sake of the elect” (2:10) because he knew the sure promises of God. (Barton, B. B., Veerman, D., & Wilson, N. S. . 1 Timothy, 2 Timothy, Titus. Life application Bible commentary Page 186. Wheaton, Ill.: Tyndale House Publishers)

THE FOLLOWING NOTE THAT THIS DEATH COULD BE EITHER SPIRITUAL OR PHYSICAL DEATH:

Wesley writes

Dead to sin, and ready to die for him.

Ryrie states that "if we died with Him" is...

"Perhaps a reference to the crucifixion of the sin nature, as in Gal. 2:20, or a reference to physical death. I.e., if we die physically, we shall be raised physically." (Ryrie Study Bible)

Geneva Study Bible feels this is...

A reference to the believer’s union with Christ in His death on the cross (New Geneva study Bible. Nashville: Thomas Nelson)

MacDonald writes that "died with Him" is...

This is true of every believer. In a spiritual sense, we died with Him the moment we trusted Him as our Savior. We were buried with Him, and we rose again with Him from among the dead. Christ died as our Representative and Substitute. We should have died for our sins, but Christ died in our place. God reckons us to have died with Him, and this means that we shall also live with Him in heaven. Perhaps this verse also has an application to those who die as Christian martyrs. Those who thus follow Him in death will likewise follow Him in resurrection." (MacDonald, W., & Farstad, A. Believer's Bible Commentary: Old and New Testaments. Nashville: Thomas Nelson) (Bolding added)

John Gill writes that "dead with him" refers to dead...

with Christ, as all his people are, by virtue of union to him; they are dead with him, he and they being one, in a legal sense; when he died, they died with him; being crucified with him, as their head and representative, their old man, their sins, were also crucified with him, being imputed to him, and laid upon him; and through the efficacy of his death, they became dead to sin, both to its damning and governing power, and so are planted together in the likeness of his death; so that as he died unto sin once, and lives again to die no more, they die unto sin, and are alive to God, and shall live for ever. Moreover, this, agreeably to what follows, may be understood of the saints dying for Christ's sake, and the Gospel, whereby they are conformed unto him, and feel the fellowship of his sufferings, and so may be said to be dead with him: and such may assure themselves of the truth of what follows,

THE FOLLOWING FAVOR THAT THIS DEATH REFERS TO PHYSICAL DEATH:

D. Edmond Hiebert, takes the following approach to the interpretation of the death that is referred to writing that...

"The first pair ("died...live") points to the results of enduring ill treatment for Christ. "If we died with him." The tense of the word "died" naturally points to a past fact. Commentators differ as to the reference. One view regards it as symbolically pointing to...Romans 6:4, 8, when the believer was united with Christ in death as a spiritual reality. But the teaching in Romans 6 occurs in an entirely different context than the present passage. The context (Ed note: There is a heavy emphasis on suffering for the gospel, not only in the letter as a whole but also in the immediate preceding context - cf suffering in 2 Ti 2:3-4, 9-10, and Paul himself is destined for a martyr's death, cf 2 Ti 4:6) here seems rather to point to physical death as the highest point of suffering for Christ. The reference is then to a martyr's death now viewed from the standpoint of the crowning day.

Hiebert goes on to reason that the purpose of this "trustworthy statement" is

to give encouragement to suffer for Christ even unto death. If loyalty to Christ for us means physical death, the assurance is that "we shall also live with Him." Faithfulness to the point of the supreme sacrifice for Christ assures us of eternal fellowship with Him in resurrection glory." (2 Timothy by D. Edmond Hiebert)

William Barclay succinctly states that...

 it is the thought of martyrdom that is in Paul’s mind. (The Daily study Bible series, Rev. ed. Philadelphia: The Westminster Press)

Guzik notes that...

The Bible speaks of dying with Jesus in two ways: The first is common to all Christians, and is illustrated by baptism: each one of us can have a "life-after-death" experience with Jesus - we can have our old life end with Jesus on the cross, and have our new life begin with His being raised from the dead. The other way the Bible speaks of dying with Jesus is, of course, in the sense of martyrdom - of paying the ultimate price for following Jesus. This is probably Paul's idea here; he is saying, "If we die with Him, we aren't dead - we live with Him." Paul could say this while on death row!

John MacArthur also mentions spiritual death but favors a physical death writing that...

If we died with Him may refer to the spiritual death of which Paul speaks in Romans. “Therefore we have been buried with Him through baptism into death,” he explains, “in order that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life. For if we have become united with Him in the likeness of His death, certainly we shall be also in the likeness of His resurrection,… for he who has died is freed from sin. Now if we have died with Christ, we believe that we shall also live with Him” (Ro 6:4–5, 7–8).

On the other hand MacArthur goes on to note that

the context of 2 Timothy 2:11 seems to suggest that Paul here has martyrdom in mind. In that case, if someone has sacrificed his life for Christ, that is, has died with Him, that martyrdom gives evidence that he had spiritual life in Him and will live with Him throughout eternity. The martyr’s hope is eternal life after death." (MacArthur, J. 2 Timothy. Chicago, Ill.: Moody Press)

WE SHALL ALSO LIVE WITH HIM : kai suzesomen (1PFAI):(Jn14:19; 2Co13:4; 1Th4:17; 5:10 Ro6:8 Jn14:19 2Co7:3 13:4 1Th4:17 5:10)

"Shall live with" (4800) (suzao from sún = together or with + záo = live) Záo is the essence of life and thus this verb combination conveys the picture that we have been entwined with the essence of Christ's life. We are identified with Him and because of His resurrection we share in and can experience the resurrection life of Jesus (walk in newness of life). Christ lives in us in the Person of the Holy Spirit. His life is in us. He is our life. In this present life and the life to come, which is likely Paul's meaning in this passage.

In the introduction of 2Timothy, Paul reminded Timothy of "the promise of life in Christ Jesus" (2Ti1:1). We were buried with Him, rose again with Him and now live in Christ.

Note that future tense (as in the present use) can be used to convey the idea of certainty and does not always refer just to a future event per se. Yes we will live with Christ in eternity future (and this should motivate us to live for Him now), but right now in eternity present we are enabled to live the Christian life because Christ lives in and through us, as we daily die to self, putting off the old filthy attitudes and actions associated with the self life and putting on the Lord Jesus Christ, manifesting the attitudes and actions of Christ, by the power of His indwelling Spirit. How else would it be possible to live like Christ? See (Ro6:8) for a similar use of the future tense to indicate certainty.

The New American Commentary deduces that...

The future tense of “we will … live” suggests that this is a reference to life in heaven. Although the reference is to heavenly life, there is a sense in which believers experience a beginning of eternal life now (John 5:24 where Jesus declared "Truly, truly, I say to you, he who hears My word, and believes Him who sent Me, has eternal life, and does not come into judgment, but has passed out of death into life.")” (Lea, T. D., & Griffin, H. P. Vol. 34: 1, 2 Timothy, Titus. The New American Commentary Page 209. Nashville: Broadman & Holman Publishers)

Hiebert summarizes this section writing that the 4 "if" statements can be divided into those who manifest belief and those who manifest unbelief...

“The central truth of these pithy statements is that faith in Christ identifies the believer with Him in everything while unbelief just as surely separates men from Him.” (Hiebert, D Edmond: Second Timothy, p. 62)

Hendriksen agrees writing that...

"If" means "If, as is the case, we are persevering..." In other words these were persevering. (see notes on Conditional Clauses)

Endure (5278) (hupomeno from hupó = under + méno = abide or remain) means literally to remain under but not simply with resignation, but with a vibrant hope. Hupomeno was a military term used of an army’s holding a vital position at all costs. Every hardship and every suffering was to be endured in order to hold fast, even as Paul was continually enduring

"all things for the sake of those who are chosen that they also may obtain the salvation which is in Christ Jesus." (2 Ti 2:12)

The present tense calls for continuous enduring. We keep on bearing up under the load (Mt24:13) in this life. We keep  persevering in and under trials and hold to one’s faith in Christ. True faith always has the quality of permanence and in this sense all believers continue to endure.

Hiebert explains that one's continued endurance...

points to this continuing experience of bravely bearing up under the hardships and afflictions heaped upon the believer because of his relation to Christ. (Hiebert then adding) "By contrast, the second pair asserts the solemn warning that denial and unfaithfulness just as surely separate men from Christ." (D. Edmond Hiebert: 2 Timothy).

Expositor's Bible Commentary adds that endure is in the present tense for...

It is only as we keep on enduring to the end that we will be saved in time of persecution (Matt 10:22; cf. context.).

Jesus declared to His disciples in the context of the difficult events that would accompany the end of the "age" (believers today still live in the same "age" as His disciples so the truth applies especially to us as we near the end of this "age" which precedes 7 years of Daniel's Seventieth Week which in turn precedes the next "age", the Messianic age when all the promises to Israel in the OT are literally fulfilled) that

"the one who endures (hupomeno) to the end, he shall be saved." (Matthew 24:13)

Don't let this verse confuse you. Jesus is not saying we will "earn" our salvation by our endurance.  Endurance does not save anyone. Only saving faith in Christ saves. Jesus' point is that the one who is genuine will endure to the end not by gritting their teeth but because the Spirit of Christ indwells them and empowers them and will never lose them. If someone turns their back on Christ after first professing Him, and persists (not a momentary event like Peter's three denials) in that apostasy, they demonstrate by their failure to endure to the end that they are not genuinely saved. The same idea of the so-called "perseverance of the saints" is seen in numerous other NT passages, especially in the epistle to the Hebrews, where we read

"Christ was faithful as a Son over His house whose house we are, if we hold fast our confidence and the boast of our hope firm until the end." (Hebrew 3:6)

"Therefore, do not throw away your confidence, which has a great reward. 36 For you have need of endurance, so that when you have done the will of God, you may receive what was promised. 37 FOR YET IN A VERY LITTLE WHILE, HE WHO IS COMING WILL COME, AND WILL NOT DELAY. 38 BUT MY RIGHTEOUS ONE SHALL LIVE BY FAITH; AND IF HE SHRINKS BACK, (which would equate with "not endure") MY SOUL HAS NO PLEASURE IN HIM. 39 But we are not of those who shrink back to destruction (note the end of those who do not endure is not loss of rewards at the Judgment Seat of Christ, but loss their life eternally in the second death - some feel "destruction" should be interpreted as a "wasted" life but note what the immediate following context refers to  - preserving of the soul, implying that destruction equates with failure to preserve one's soul, i.e., an unbeliever and not just the wasted life of a believer), but of those who have faith to the preserving of the soul. (Hebrews 10:35-39)

The reward of enduring now is not only that we prove our salvation genuine but that we are also rewarded with reigning as discussed in the coming Messianic Age and then the New Heaven and New Earth..

Charles Ryrie writes that

"If we endure in this life, we shall reign in our glorified state" (Ryrie Study Bible)

WE SHALL ALSO REIGN WITH HIM : kai sumbasileusomen (1PFAI): (Revelation 1:6,9; 5:10; 20:4,6)

"Reign with" (4821) (sumbasileuo from sun = together with + basileúo = to reign as king) means to be a coregent. Note that the preposition in this compound (and also in "died with" and "live with" above) is sun which conveys the sense of union with. It speaks of a more intimate association than does another Greek preposition (meta) which also means with. In context sun speaks of our inseparable identification with Christ.

Paul is referring to the saints as reigning as kings with the King of kings in the Messianic Kingdom.

Jesus promised that

"he who overcomes (see explanation below as to the identity of overcomers) and he who keeps My deeds until the end, TO HIM I WILL GIVE AUTHORITY OVER THE NATIONS AND HE SHALL RULE THEM WITH A ROD OF IRON, AS THE VESSELS OF THE POTTER ARE BROKEN TO PIECES, as I also have received authority from My Father." (Rev 2:26-27)

Jesus in another promise to the overcomers (Jesus gives promises to overcomers in His address to each of the 7 churches of Revelation 2-3) at the church in Laodicea says that

"He who overcomes, I will grant to him to sit down with Me on My throne, as I also overcame and sat down with My Father on His throne." (Rev 3:21)

Overcomers are not some select group of saints for John teaches us that...

whatever is born of God overcomes the world; and this is the victory that has overcome the world-- our faith. And who is the one who overcomes the world, but he who believes that Jesus is the Son of God? (1 John 5:4-5)

The apostle John describes the future events in heaven in which the Lamb Who was slain received the sealed scroll (probably the "title deed" to the earth) from the Father prompting those who witnessed this event to sing a new song saying which includes a promise describing where saints will reign...

"Worthy art Thou to take the book, and to break its seals; for Thou wast slain, and didst purchase (our Kinsman Redeemer paid the purchase price in full when He shed His precious blood like a lamb) for God with Thy blood men from every tribe and tongue and people and nation. And Thou hast made them to be a kingdom ("kings" KJV) and priests to our God; and they will reign upon the earth." (Rev 5:9-10)

John describing the glorious Millennial kingdom of Christ on the earth (with the present curse removed, eg see Isaiah 11:6ff)  writes

"And I saw thrones, and they sat upon them, and judgment was given to them (in 1Cor 6:2-3 Paul asks "do you not know that the saints will judge the world? And if the world is judged by you, are you not competent to constitute the smallest law courts? Do you not know that we shall judge angels? How much more, matters of this life?"). And I saw the souls of those who had been beheaded because of the testimony of Jesus and because of the word of God (during the great tribulation, e.g. see Rev 7:14), and those who had not worshiped the beast or his image, and had not received the mark upon their forehead and upon their hand; and they came to life (i.e., were resurrected) and reigned with Christ for 1000 years ("Millennium"). The rest of the dead (all those of all the ages who are still dead in their trespasses and sins) did not come to life until the 1000 years were completed (at the Great White Throne judgment where only spiritually dead will stand for sentencing to the Lake of fire). This is the first resurrection (this reference is not to "the dead" but to those beheaded who were resurrected and includes all believers of all ages who were resurrected at different "stages" of the "first resurrection, "but each in his own order: Christ the first fruits, after that those who are Christ's at His coming," 1Cor 15:23). Blessed and holy is the one who has a part in the first resurrection; over these the second death has no power (thus this resurrection includes all believers for over them the 2nd death has no power), but they will be priests of God and of Christ and will reign with Him for a 1000 years." (Rev 20:4-6)

John describing the time of the New Heaven and New Earth (the "age" that follows the Messianic Age or the 1000 year reign of Christ on earth) declares that...

there shall no longer be any night; and they shall not have need of the light of a lamp nor the light of the sun, because the Lord God shall illumine them; and they shall reign forever and ever. (Rev 22:5)

The other side of that truth is that those who do not endure give evidence that they do not belong to Christ and will not reign with Him.

Paul writes that we are

"heirs of God and fellow heirs with Christ, if indeed we suffer with Him in order that we may also be glorified with Him." (Ro8:17).

In his devotional "Morning and Evening" Spurgeon writes...

“If we suffer, we shall also reign with him.” 2 Timothy 2:12 We must not imagine that we are suffering for Christ, and with Christ, if we are not in Christ. Beloved friend, are you trusting to Jesus only? If not, whatever you may have to mourn over on earth, you are not “suffering with Christ,” and have no hope of reigning with him in heaven. Neither are we to conclude that all a Christian’s sufferings are sufferings with Christ, for it is essential that he be called by God to suffer. If we are rash and imprudent, and run into positions for which neither providence nor grace has fitted us, we ought to question whether we are not rather sinning than communing with Jesus. If we let passion take the place of judgment, and self-will reign instead of Scriptural authority, we shall fight the Lord’s battles with the devil’s weapons, and if we cut our own fingers we must not be surprised. Again, in troubles which come upon us as the result of sin, we must not dream that we are suffering with Christ. When Miriam spoke evil of Moses, and the leprosy polluted her, she was not suffering for God. Moreover, suffering which God accepts must have God’s glory as its end. If I suffer that I may earn a name, or win applause, I shall get no other reward than that of the Pharisee. It is requisite also that love to Jesus, and love to his elect, be ever the mainspring of all our patience. We must manifest the Spirit of Christ in meekness, gentleness, and forgiveness. Let us search and see if we truly suffer with Jesus. And if we do thus suffer, what is our “light affliction” compared with reigning with him? Oh it is so blessed to be in the furnace with Christ, and such an honour to stand in the pillory with him, that if there were no future reward, we might count ourselves happy in present honour; but when the recompense is so eternal, so infinitely more than we had any right to expect, shall we not take up the cross with alacrity, and go on our way rejoicing?

IF WE DENY HIM HE WILL ALSO DENY US: ei arnesometha (1PFMI) kakeinos arnesetai (2SFMI) hemas: (Pr30:9; Mt10:33; 26:35,75; Mk 8:38; Mt10:33; Lu9:26; 12:9; 1Jn 2:22; 1Jn2:23; Jude4; Rev2:13; 3:8)

It is interesting that the NIV translators choose "disown" instead of "deny":

."If we disown him, he will also disown us"

Edwards comments on...

"why NIV changed the familiar "deny" to "disown." The reason is that "deny" means primarily "to declare untrue; assert the contrary of, contradict," whereas "disown" means "to refuse to acknowledge or accept as one's own" (American Heritage Dictionary). Thus, "disown" was more accurate when applied to persons as its object." (2Timothy  Call to Completion).

"Disown" is a strong word that leaves little doubt as to the intention of the NIV translators. Webster defines "disown" as

"to refuse to acknowledge as one’s own, to repudiate any connection or identification with" (Merriam-Webster's Collegiate Dictionary)

The Amplified version renders this verse quite graphically...

"If we deny and disown and reject Him, He will also deny and disown and reject us."

Note that the "If" (ei) means "If, as is the case, we are denying Him..." (see the following note) In other words this is a true statement - some were denying Him even in this letter to Timothy...

"You are aware of the fact that all who are in Asia turned away from me, among whom are Phygelus and Hermogenes." (1:15)

"their talk will spread like gangrene. Among them are Hymenaeus and Philetus, men who have gone astray from the truth saying that the resurrection has already taken place, and thus they upset the faith of some." (2:17-18)

"holding to a form of godliness, although they have denied its power; and avoid such men as these" (3:5)

"And just as Jannes and Jambres opposed Moses, so these men also oppose the truth, men of depraved mind, rejected as regards the faith." (3:8)

"For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires; and will turn away their ears from the truth, and will turn aside to myths." (4:3-4)

"Demas, having loved this present world, has deserted me and gone to Thessalonica; Crescens has gone to Galatia, Titus to Dalmatia." (4:10)

"At my first defense no one supported me, but all deserted me; may it not be counted against them." (4:16)

Now the question one might raise about all these "denials" in 2 Timothy is whether they were of the "Petrine type" (transient) or the "Judas type" unto perdition and frankly it is only God who knows the heart of each of these individuals or groups. We don't have enough information on most of them to make a reasoned assessment. Certainly some appear to be clearly unbelievers, but we will leave that with God.

Wuest notes that...

"The “if” with “deny” and “believe not” is ei, the particle of a fulfilled condition. Some were denying Him and were unfaithful." (Wuest, K. S. Wuest's Word Studies from the Greek New Testament. Grand Rapids: Eerdmans) (Bolding added)

O Jesus, I have promised To serve Thee to the end;
Be Thou forever near me, My Master and my Friend:
I shall not fear the battle If Thou art by my side,
Nor wander from the pathway If Thou wilt be my Guide.
(Click hymn)

"Deny" (720) (arneomai from a = negation + rheo = utter, speak or say) literally means "to say no", to say one does not know about or is in any way related to some person or some thing. Arneomai means to refuse to agree or consent to something, to disclaim connection with or responsibility for, to say one does not know about or is in any way related to a person or event. To deny carries idea of conscious, purposeful action of one's will.

One can discern two "types of denial" as exemplified in the following passages:

A SETTLED DENIAL

Jesus seems to speak of a denial by one's words declaring that...

"Everyone therefore who shall confess Me before men, I will also confess him before My Father who is in heaven. But whoever shall deny Me before men, I will also deny him before My Father who is in heaven." (Mt 10:32-33)

John ask rhetorically...

Who is the liar but the one who denies (present tense) that Jesus is the Christ? This is the antichrist, the one who denies (present tense = continually, habitually, what what they say and how they live) the Father and the Son. Whoever denies (present tense) the Son does not have the Father; the one who confesses (present tense)  the Son has the Father also. (1Jn 2:22; 23)

A TRANSIENT DENIAL

Luke records the events following Peter's denial of His Lord...

And the Lord turned (being carried away by the Roman soldiers) and looked at Peter. And Peter remembered the word of the Lord, how He had told him, "Before a cock crows today, you will deny Me three times." And he went out and wept bitterly (Note Peter's reaction to his denial). (Luke 22:61)

Matthew records that when Judas who denied Jesus by his deeds more than his words

"saw that He had been condemned, he felt remorse (regret but not repentance) and returned the thirty pieces of silver to the chief priests and elders" (Mt 27:3)

Judas did not have a godly sorrow, for as Paul explains...

"the sorrow that is according to the will of God produces a repentance without regret, leading to salvation; but the sorrow of the world produces death." (2 Cor 7:10)

Peter on the other hand did not just have a deep emotional reaction but a heart change brought forth fruit in keeping with his genuine repentance. Peter some 40 plus days after his denial of Jesus was brought before the Jewish ruling council in Jerusalem (Sanhedrin), was scourged (thrashing which resulted in the removal one's skin) for teaching about Jesus and was ordered to speak no more in the Name of Jesus. Luke records that in contrast to his previous "thrice denial", he and the other believers...

"went on their way from the presence of the Council, rejoicing (Peter and the others having been empowered by the Holy Spirit) that they had been considered worthy to suffer shame for His Name. (Acts 5:41)

The point of these passages is that there can be transient denial of Jesus or a settled denial of Jesus in which one persistently rejects Jesus as Lord and Savior. Clearly, the former circumstance represents a believer who is momentarily unfaithful whereas the latter group represents those who refuse to believe in Jesus. Which group is Paul referring to in this trustworthy statement "if we deny Him, He will deny us"? There is considerable divergence of opinion among the commentaries as discussed below. Take for example Demas in 2 Timothy 4:10. Was his desertion of Paul a momentary lapse or an indication of an unregenerate heart? Frankly, I don't think one can be absolutely dogmatic. Ultimately only God knows whether a man's denial is like Peter's "thrice denial" or represents a settled state of mind and heart. Paul's warning is that if one does exhibit a settled denial of Christ, then Christ will certainly deny that individual.

Jesus plainly taught that...

 "Everyone therefore who shall confess Me before men, I will also confess him before My Father who is in heaven. But (note this strong contrast is clearly with those who are genuinely saved and that there is no mention of rewards in this context) whoever shall deny Me before men, I will also deny him before My Father Who is in heaven." (Mt 10:32-33)

In the interest of being "fair and balanced", it should be noted that some commentators such as Warren Wiersbe (who I highly respect) interpret the denial in this "trustworthy statement" not as a denial which is permanent but which is temporary. These writers are forced to interpret the denial by Christ not as a denial that He knows them (so that they are not believers) but as a denial of rewards at the Judgment Seat of Christ. Thus they will not receive the rewards they would have had they not denied Him. This latter interpretation is "weak" because the statement specifically declares "He will deny us" not "He will deny us rewards" (see the following excellent technical note from the Net Bible). The plain reading of the "trustworthy statement" therefore favors the interpretation of the denial by Christ as not being a denial of rewards but of the individuals themselves. The result of this denial is eternal separation from God and the Lord Jesus Christ.

The NET Bible Note addresses the above interpretation writing that deny can be translated...

"renounce, disown, repudiate. It is important to note that the object of Christ’s denial is “us.” The text does not contain an implied object complement (“he will deny us [x]”), which would mean that Christ was withholding something from us (for example, “The owner denied his pets water”) (Ed note: e.g. the text does not say He will "deny us [rewards]"), since the verb arneomai is not one of the category of verbs that normally occurs in these constructions (see Greek Grammar Beyond the Basics: An Exegetical Syntax of the New Testament. 182–8 9)." (The NET Bible Notes  Biblical Studies Press) (Bolding added)

Marvin Vincent, author of the respected "Word Studies in the NT" which emphasizes the original Greek text writes that...

"Him (the object of the first deny) must be supplied. (Vincent then goes on to declare that...) The meaning of the last clause is, will not acknowledge us as His own." (Vincent, M. R. Word studies in the New Testament. Vol. 4, Page 300)

 The IVP Bible Background Commentary concludes that...

The faithfulness of God to His covenant is not suspended by the breach of that covenant by the unfaithful; but those individuals who break his covenant (Ed note: I think more accurately those who never entered into the New Covenant, for once truly united in Covenant with Christ they can never be lost) are not saved (Keener, C. S., & InterVarsity Press. The IVP Bible background commentary : New Testament. Downers Grove, Ill.: InterVarsity Press)

The IVP New Testament Commentary note writes that Paul's...

"tone changes dramatically in the last two lines of verse 12: if we disown him, he will also disown us. This warning has the treachery of apostasy in view. Both the we and the us, as well as the language of denial (1 Tim 5:8; 2 Tim 3:5; Titus 1:16), show that Paul is thinking of rejection of the faith by those who profess it. Not only actual false teaching but also a rejection of the call to endure give evidence of a decision to deny Christ. Jesus’ own words may lie behind this warning: “whoever disowns me before men, I will disown him before my Father in heaven” (Mt10:33). In that context too faithfulness includes a willingness to suffer, struggle and die. Rejection by Christ means exclusion from eternal life." (Towner, P. 1-2 Timothy & Titus: The IVP New Testament Commentary Series. Downers Grove: InterVarsity) (Bolding added)

John MacArthur writes that this denial

"Speaks of a final, permanent denial, such as that of an apostate, not the temporary failure of a true believer like Peter (Mt26:72). Those who so deny Christ give evidence that they never truly belonged to Him (1Jn2:19) and face the fearful reality of one day being denied by Him (Mt10:33)." (MacArthur, J. J.  The MacArthur Study Bible. Nashville: Word Pub) (Bolding added)

In his commentary on 2 Timothy, MacArthur adds that...

The Greek verb rendered deny is in the future tense, and the clause is therefore more clearly rendered, “If we ever deny Him” or “If in the future we deny Him.” It looks at some confrontation that makes the cost of confessing Christ very high and thereby tests one’s true faith. A person who fails to endure and hold onto his confession of Christ will deny Him, because he never belonged to Christ at all." (MacArthur, J. 2 Timothy. Chicago, Ill.: Moody Press)

J Vernon McGee comments that Christ's denial of us

"is very strong language. It reveals, however, that Paul believes that faith without works is dead (Js2:17 " Even so faith, if it has no works, is dead, being by itself."). You see, Paul and James never contradict each other. James is talking about the works of faith, and Paul is saying that genuine faith will produce works. Calvin put it like this:

“Faith alone saves, but the faith that saves is not alone."

(McGee, J. V. Thru the Bible commentary. Nashville: Thomas Nelson)

Charles Ryrie agrees writing that...

"Those who deny are professing (Ed note:  profess = declare in words or appearances only) people who will in turn be disowned by Him (Mt10:33; 2 John 1:9)." (Bolding added)

Albert Barnes (referring to his related comment on Jesus' denial in Mt 10:33) writes...

We must be ashamed neither of the person, the character, the doctrines, nor the requirements of Christ. If we are; if we deny him in these things before people; if we are unwilling to express our attachment to him in every way possible, then it is RIGHT that he should "disown all connection with us," or deny us before God, and he WILL do it. (Barnes, A: Notes on the NT)

Expositor's Bible Commentary adds that...

"The third proposition is negative: "If we disown him" (aorist tense, arnesometha), "he will also disown us." This is a serious warning. We cannot reject Christ without being rejected ourselves." (Bolding and color added)

Hendriksen writes that

"When a person, because of unwillingness to suffer hardship for the sake of Christ and his cause, disowns the Lord (“I do not know the man!”), then, unless he repents (as Peter did after his denial), he will be disowned by the Lord in the great day of judgment (“I do not know you”)." (Hendriksen, W., & Kistemaker, S. J.  Vol. 4: New Testament commentary : Exposition of the Pastoral Epistles. Page 259. Grand Rapids: Baker Book House) (Bolding added)

William MacDonald comments that...

"Those who deny Christ will be denied by Him. Here the thought is not of a temporary denial of the Savior under duress, as in the case of Peter, but a permanent, habitual denial of Him. These words describe an unbeliever—one who has never embraced the Lord Jesus by faith. All such will be denied by the Lord in a coming day, no matter how pious their profession might have been." (MacDonald, W., & Farstad, A. Believer's Bible Commentary: Old and New Testaments. Nashville: Thomas Nelson) (Bolding added)

The Bible Knowledge Commentary agrees that the denial referred to here

"speaks of the possibility of apostasy and the Lord’s ultimate rejection of those who professed Christ only temporarily. Instead of identifying with Christ, the apostate finally dissociates himself with Christ." (Walvoord, J. F., Zuck, R. B. The Bible knowledge commentary: An exposition of the scriptures. Wheaton, IL: Victor Books) (Bolding added)

To reiterate Paul is not saying a momentary or transient denial of Christ indicates one is not a believer and will be denied by Christ. What Paul is describing is a settled, final denial that does not repent and thereby gives amply evidence of that individual's unregenerate heart. Note that Paul is not teaching that you can be genuinely saved and then lose your salvation. Scripture repeatedly underscores the eternal security of the one who is genuinely born from above by the regenerating work of the Spirit. This passage however should be a strong warning to those who have given a "mouth profession" ("mental assent") that they belief but who do not have a "heart possession" of Christ, and who demonstrate their unregenerate heart by their persistent denial of Christ be it through their attitude, their words, their actions or their overall lifestyle.

D. Edmond Hiebert commenting on the phrase "deny...deny" writes that

"By contrast, the second pair ("deny...deny") asserts the solemn warning that denial and unfaithfulness just as surely separate men from Christ. "If we deny him" points to an awful possibility. Jesus Himself emphatically warned of the danger (Mt 10:33 "But whoever shall deny Me before men, I will also deny him before My Father who is in heaven"; Mark 8:38 "For whoever is ashamed of Me and My words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when He comes in the glory of His Father with the holy angels."). To close our eyes to this warning would be folly. William Kelly comments:

"There was danger in a day of declension particularly of departure not only from this or that divine principle but from Himself, and this permanently. Nor does the apostle bolster up the saints in what is the most dangerous delusion, that there is no danger. For dangers abound on all sides; and we ought to know that grievous times were to come in the last times."

To "deny him" here does not point merely to a temporary weakness of faith, as in the case of Peter (Luke 22:54­62), but as the conclusion shows, means to deny our relation with Him as a permanent fact. The inevitable result is that "he also will deny us."

The warning is repeated in the final sentence, "if we are faithless, he abideth faithful." To be "faithless" means to give up one's faith and the present tense denotes this as the habitual attitude, not a temporary lapse or obscuration (concealing) of faith. But in contrast to human faithlessness, "he abideth faithful," faithful to His warning that the unbelieving will be rejected.

"Christ will never depart from that solemn word, which pledges Him, at the last day, to own those who have owned Him, and to deny those who have denied Him" (Harvey).

His unchanging faithfulness arises out of the fact of His immutable nature. This is confirmed by the concluding statement which amplifies all of the preceding statements and forms the capstone for the whole. "For he cannot deny himself." As the unchanging Jehovah whose very nature is truth, He cannot be false to His own nature, nor to His word of promise to the faithful and His word of threatening to the faithless." (Hiebert, D E: 2 Timothy).

While the consensus of conservative commentaries interpret "if we deny Him" as indicative of an unbeliever, not everyone agrees. Thomas Constable is one such writer who makes an incredible statement which begins concluding that this a warning and goes on to explain that...

"If the believer departs from following Christ faithfully during his or her life (i.e., apostatizes), Christ will deny him or her at the judgment seat of Christ (Matt. 10:33; Mark 8:38; Luke 12:9; cf. Luke 19:22; Matt. 22:13). The unfaithful believer will not lose his salvation (1 John 5:13) or all of his reward (1 Pet. 1:4), but he will lose some of his reward (1 Cor. 3:12–15; cf. Luke 19:24–26). To deny Christ clearly does not mean to deny Him only once or twice (cf. Luke 22:54–62) but to deny Him permanently since the other three human conditions in the couplets are permanent." (Constable, T. Tom Constable's Expository Notes on the Bible) (Bolding added)

Constable is implying that even those who deny Christ permanently are not unbelievers but at worst "apostatized" believers! Although this website does quote Constable occasionally, the discerning reader will note that he has frequent comments of this type in dealing with issues of genuine salvation and the evidence of such, so due caution is recommended when consulting his commentary.

John gives us an example of those who initially claimed to believe and accept Christ but who later denied Him when the cost became too high. John writes that because many of the things the Lord Jesus had taught in the preceding verses proved so distasteful "many of His disciples withdrew, and were not walking with Him anymore." (Jn6:66) John's language indicates that the abandonment was decisive and final. In other words, many of the Jews who had previously followed Him, now left Him and were no longer willing to associate with Him. These "disciples" were never true "disciples" or genuine believers. They followed the Lord for various reasons, but not out of genuine love for Him or acceptance of Who He was.

Life Application Bible Commentary writes that "deny...deny"...

"reveals that commitment to Christ must be total, no turning back; to disown results in being disowned. The Greek tense in the phrase “if we disown” is future. These words provided a solemn warning; but to deny Christ was unthinkable to the early Christians, even in the face of mounting persecution. True believers might be faithless and weak at times; they might falter when giving a testimony, but they would never disown their Lord. While the word deny has been used in place of “disown” (NRSV, NKJV), the meaning here implies deliberate refusal of Jesus as Lord. Jesus had already issued the warning:

“Whoever acknowledges me before men, I will also acknowledge him before my Father in heaven. But whoever disowns me before men, I will disown him before my Father in heaven” (Matthew 10:32–33 niv).

The writer of Hebrews assured the faithful believers that

“we are not among those who shrink back and so are lost, but among those who have faith and so are saved” (Hebrews 10:39 NRSV)."

(Barton, B. B., et al: Life application Bible commentary Wheaton, Ill.: Tyndale House Publishers) (Bolding added)

The Geneva Study Bible writes that here Paul gives...

"A sober warning against apostasy (abandonment of a previous loyalty, abandonment of one’s religious faith, defection from the faith)"

The Nelson study Bible comments that "deny us" is...

"A warning against apostasy. Jesus will not save those who shrink from identifying with Him or from serving Him on this earth." (Radmacher, E. D., et al: The Nelson Study Bible: New King James Version. Nashville: T. Nelson Publishers) (Bolding added)

Matthew Poole writes that...

"...if we, upon prospect of danger, deny his truth, or desert the profession of Him, He in the day of judgment will not own us before His Father and the holy angels." (Matthew Poole's Commentary on the New Testament)

The KJV Bible Commentary has an interesting note that...

"the Greek verb here is future, “if we shall deny him.” Two things to remember here. First, Peter denied Christ three times, even though he was saved, but his reaction was conviction and contrition (Luke 22:61 records "And the Lord turned and looked at Peter. And Peter remembered the word of the Lord, how He had told him, "Before a cock crows today, you will deny Me three times. And he went out and wept bitterly."). Secondly, I John 2:19 tells of those who

“went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.”

These were apostate. It must be remembered man only sees the outward, God sees the heart (1 Sam 16:7)." (KJV Bible commentary. Nashville: Thomas Nelson) (Bolding added)

In a similar vein Jon Courson comments that...

“I never knew the man,” Peter cursed vehemently (Mt26:74). Yet after His Resurrection, Jesus found Peter personally and ministered to him tenderly (John 21:16 "He said to him again a second time, "Simon, son of John, do you love Me?" He said^ to Him, "Yes, Lord; You know that I love You." He said^ to him, "Shepherd My sheep."). Thus, this verse doesn’t refer to those who stumble like Peter, but to those who decide repeatedly that they want nothing to do with Jesus." (Courson, J. Jon Courson's Application Commentary. Page 1403. Nashville, TN: Thomas Nelson) (Bolding added)

So although not every commentator agrees, the consensus seems to be that Paul's thought in this verse is not of a temporary denial of the Savior under duress, as in the case of Peter, but a permanent, habitual denial of Him. These words describe an unbeliever—one who has never embraced the Lord Jesus by faith. All such will be denied by the Lord in a coming day, no matter how pious their profession might have been. Those who interpret this first "deny" as reflective of a "backslidden" believer, are forced to explain the denial by Christ as a denial of rewards for unfaithfulness. Although certainly faithfulness will determine rewards, the text does not make that statement. To "soften" the message in my opinion does grave injustice to Paul's somber warning.

C H Spurgeon exhorts us to

"If we are faithless" can be rendered "In view of the fact that we are unfaithful" Paul is saying some were were unfaithful which refers to a lack of saving faith, not to weak or struggling faith. Unbelievers will ultimately deny Christ because their faith was not genuine.

"Are faithless" (569) (apisteo from a = without + pistós = believing) means to be unfaithful, to doubt or not to acknowledge. This verb is in the present tense which pictures a continual, habitual unfaithfulness as shown by  what they say and how they live. In context the implication is that a habitually "faithless" person is one who does not endure to the end and ultimately is one who denies Christ. The unsaved ultimately deny Christ, because they never had faith in Him for salvation.

Let's look at two (out of only 6) uses of apisteo in the NT to help understand the meaning of this verb, and possibly shed some light on how one might interpret the present passage...

Peter uses apisteo to contrast believers and unbelievers writing that...

"This precious value (Jesus Christ, our precious Cornerstone), then, is for you who (continually) believe (present tense). But for those who (continually) disbelieve (apisteo in the present tense) "THE STONE WHICH THE BUILDERS REJECTED, THIS BECAME THE VERY CORNER stone," 8 and, "A STONE OF STUMBLING AND A ROCK OF OFFENSE"; for they stumble because they are disobedient to the word, and to this doom they were also appointed." (1 Peter 2:7-8)

Paul uses a similar combination of apisteo and pistis (faith, faithfulness) in Romans writing...

"What then? If some did not believe (apisteo), their unbelief (apistia) will not nullify the faithfulness (pistis) of God, will it? (The New Living Translation renders it "True, some of them were unfaithful; but just because they broke their promises, does that mean God will break his promises?") (Romans 3:3) (Note the way this question is phrased in the Greek expects a negative answer!)

The interpretation of this verse is "problematic", some interpreting the "continually faithless" or "continually disbelieving" as believers who exhibit a lapse of faith (which from the present tense would have to be more of a lifestyle than a single lapse here and there) and the other camp which interprets these as unbelievers. If some one says they are a believer and yet by their life they continually manifested faithlessness to the end of their life, it seems unconscionable to label such a one as a genuine, "new creature in Christ". Note that Paul is not saying these were believers who now have lost their salvation because of their continual unfaithfulness, for this conclusion would counter numerous verses that undergird the security of the believer's salvation, assuming that it is a genuine conversion experience and the individual is a new creature in Christ as shown by the fact that the old life is gone and a new life has begun!

Expositor's Bible Commentary writes...

""If we are faithless" is in the present tense (apistoumen), indicating a settled state of refusing to believe in Jesus and obey him. But whatever we do, "he will remain faithful, for he cannot disown himself." God's faithfulness is eternal." (Bolding added)

Marvin Vincent writes that "If we believe not" is better translated...

"are faithless or untrue to him. Cp. Ro 3:3 (which reads "What then? If some did not believe, their unbelief will not nullify the faithfulness of God, will it?"). In Pastorals only here.  (Vincent, M. R. Word Studies in the New Testament. Vol. 4, Page 300).

MacDonald comments that...

This verse also describes unbelievers. Dinsdale Young explains: “God cannot be inconsistent with Himself. It would be inconsistent with His character to treat the faithful and the unfaithful alike. He is evermore true to righteousness, whatever we are.” The words should not be interpreted to teach that God’s faithfulness will be demonstrated in upholding those who are unbelieving. Such is not the case. If men are unbelieving, He must be faithful to His own character and must treat them accordingly. As Van Oosterzee says, “He is just as faithful in His threatenings as in His promises.” (MacDonald, W., & Farstad, A. Believer's Bible Commentary. Nashville: Thomas Nelson) (Bolding added)

John MacArthur writes that

In this context, apisteō (are faithless) means lack of saving faith, not merely weak or unreliable faith. The unsaved ultimately deny Christ, because they never had faith in Him for salvation." (MacArthur, J.  2 Timothy. Chicago, Ill.: Moody Press)

McGee writes that...

God “cannot deny himself.” He cannot accept as true one who is false. That’s the reason He gave such a scathing denunciation of the religious rulers of His day. He called them hypocrites because they were pretending to be something they were not. If Christ accepted someone who is not genuine, He actually would be denying Himself because He is true. Therefore, we should be genuine, my friend. (McGee, J. V.  Thru the Bible commentary. Vol. 5, Page 466. Nashville: Thomas Nelson) (Bolding)

The People's NT Commentary writes that...

 If we prove faithless, he will still be faithful to keep every promise he has made.

Spurgeon in his sermon "Eternal Faithfulness Unaffected by Human Unbelief" (click full sermon)

One of the most shocking trials to young Christians is the fall of an eminent teacher. I have known some that have been almost ready to give up their faith when some one who appeared to be very earnest and faithful has suddenly apostatized. Such things have happened in our memory, to our intense grief; and I want, therefore, to put it very, very plainly. If it should come to pass that any one whom you revere as having been best to your soul — whom you because you have received from him the word of life — -if such a one upon whom you may perhaps have learned too much should in the future turn out not to be true and faithful, and should not believe, do not follow his unbelief, for “if we believe not, yet he abideth faithful: he cannot deny himself.” Peter denies his Master: do not follow Peter when he is doing that, for he will have to come back weeping, and you will hear him preaching his Master again. Worse still, Judas sells his Master: do not follow Judas, for Judas will die a wretched death, and his destruction shall be a warning to others to cling more closely to the kith. You may See the man who stood like a cedar in Lebanon fall by one stroke of the devil’s axe, but do not, therefore, think that the trees of the Lord, which are fall of sap, will fall too. He will keep his own, for he knows them that are his. Pin not your faith to any man’s sleeve. Let not your confidence rest on any arm of flesh, neither say “I believe because of the testimony of such a one, and I hold to the form of sound words because my minister has held it”; for all such props may be smitten; away and on a sudden may fail you. Do let me put this very, very plainly, — if we believe not — if those that seem to be the choice teachers of the age, if those that have been the most successful evangelists of the period, if those who stand high in the esteem of God’s people, should, in an evil hour, forsake the eternal verities and begin to preach to you some other gospel which is not the gospel of Jesus Christ, I beseech you follow us not whoever we may be or whatever we may be. Suffer no teachers however great they may be, to lead you to doubt for God abideth faithful. Keep you to the revealed will and mind of God — for “he cannot deny himself.

HE REMAINS FAITHFUL: ekeinos pistos menei (3SPAI): (Is 25:1; Mt24:35; Ro3:3; 9:6; 1Th5:24; 2Th3:3) Click for more discussion of faithfulness one of God's wonderful attributes. Click for sermon by Alexander Maclaren entitled "A Faithful God "

"Remains" (3306) (meno) (present tense) means He continually abides faithful. In reference to state or condition (such as faithful) it means to remain as one and so not to become another or different. His faithfulness is unchanging or immutable.

"Faithful" (4103) (pistos) means trustworthy, dependable, reliable. Worthy of belief, trust, or confidence. For Christ to abandon us would be contrary to His faithful nature. Jesus remains faithful, not only to those who believe in Him but to those who do not in this last section of the "trustworthy statement". Jesus is faithful to all of His promises, whether they promise good or judgment. .

Marvin Vincent explains that "faithful" means...

"True to his own nature, righteous character, and requirements, according to which he cannot accept as faithful one who has proved untrue to him. To do this would be to deny himself. (Vincent, M. R. Word Studies in the New Testament. Vol. 4, Page 300).

Hendriksen concludes that...

Divine faithfulness is a wonderful comfort for those who are loyal (I Thess. 5:24; II Thess. 3:3; cf. I Cor. 1:9; 10:13; II Cor. 1:18; Phil. 1:6; Heb. 10:23). It is a very earnest warning for those who might be inclined to become disloyal. (Hendriksen, W., & Kistemaker, S. J. Vol. 4: New Testament commentary: Page 260. Grand Rapids: Baker Book House) (Bolding added)

MacArthur writes that

As faithful as Jesus is to save those who believe in Him (John 3:16), He is equally faithful to judge those who do not (John 3:18). To act any other way would be inconsistent with His holy, unchangeable nature. (MacArthur, J. J. The MacArthur Study Bible Nashville: Word Pub)

Spurgeon commenting on this passage writes...

Glory be to God, the unbelief of man cannot make God break his promises. Christian, all thine unbelief has not made God unfaithful to thee: and sinner, though thou cast out the promise of God as being good for nothing, yet he will not therefore raise the recompense of reward, for Jesus will save others if he save not thee. “He abideth faithful.”

Great is Thy faithfulness, O God my Father,
There is no shadow of turning with Thee;
Thou changest not, Thy compassions they fail not;
As Thou hast been Thou forever wilt be. (click hymn)

The Scripture is replete with testimony to the perfect faithfulness of our Lord as shown by the following sample of passages...

Know therefore that the LORD your God, He is God, the faithful God, who keeps His covenant and His lovingkindness to a thousandth generation with those who love Him and keep His commandments (Dt 7:9)

Faithful is He who calls you, and He also will bring it to pass. (1Th5:24)

For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus. (Phil 1:6)

Therefore, He had to be made like His brethren in all things, that He might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people. (Heb 2:17)

He (Jesus) was faithful to Him who appointed Him, as Moses also was in all His house. (Heb 3:2)

Let us hold fast the confession of our hope without wavering, for He who promised is faithful (Heb 10:23)

By faith even Sarah herself received ability to conceive, even beyond the proper time of life, since she considered Him faithful Who had promised (Heb 11:11)

Jesus Christ is the same yesterday and today, yes and forever. (Heb13:8)

If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. (1 John 1:9)

FOR HE CANNOT DENY HIMSELF: arnesasthai (AMN) gar heauton ou dunatai (3SPPI): (Nu23:19; Titus1:2; Heb6:18)

"Not" (ou) indicates absolute negation in the Greek (in contrast to the relative negation with the Greek word "me") . In other words, there is absolutely no way Christ is able to deny Himself.

"Can" (1410) (dúnamai) means to have power by virtue of inherent ability and resources. To be able. Robertson writes that here in verse 13 deny "has the notion of proving false to oneself, a thing that Christ “cannot”." Dunamai is in the present tense which pictures Jesus as never able to deny Himself.

Moses (who had numerous personal encounters with God) testified that "God is not a man, that He should lie". (Numbers 23:19). Paul echoes this truth from His personal experience that God is (literally) the "non-lying God" (Titus1:2)

"Deny" (720) (arneomai from a = negation + rheo = utter, speak or say) literally means "to say no", to say one does not know about or is in any way related to some person or some thing. Arneomai means to refuse to agree or consent to something, to disclaim connection with or responsibility for, to say one does not know about or is in any way related to a person or event. To deny carries idea of conscious, purposeful action of one's will. 

As Spurgeon has said there are...

Three things God cannot do. He cannot die, he cannot lie, and he cannot be deceived. These three impossibilities do not limit his power, but they magnify his majesty; for these would be infirmities, and infirmity can have no place in the infinite and ever blessed God. (Eternal Faithfulness Unaffected by Human Unbelief)

Why is it impossible for Jesus to deny Himself? Because He is Truth and to the end He remains Faithful and True (Rev 19:11) (the Word of God in Rev 19:13)  Just as Christ will never renege on His promise to save those who trust in Him, He also will never renege on His promise to condemn those who do not. To do otherwise would be to deny Himself, which His righteous and just nature cannot allow Him to do.

J Vernon McGee adds that...

God “cannot deny himself.” He cannot accept as true one who is false. That’s the reason He gave such a scathing denunciation of the religious rulers of His day. He called them hypocrites because they were pretending to be something they were not. If Christ accepted someone who is not genuine, He actually would be denying Himself because He is true. Therefore, we should be genuine, my friend. (McGee, J. V.  Thru the Bible commentary. Vol. 5, Page 466. Nashville: Thomas Nelson)

It was on the basis of Christ’s absolute faithfulness that Paul declared earlier in this letter,

“I know Whom I have believed and I am convinced that He is able to guard what I have entrusted to Him until that day” (2Ti1:12).

What did Jesus say in Mt 7:21-23 that conveys a similar somber warning to that found in this trustworthy statement?

"Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven; but he who does the will of My Father who is in heaven. Many will say to Me on that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?' "And then I will declare to them, 'I never knew you; DEPART FROM ME, YOU WHO PRACTICE (present tense) LAWLESSNESS.'

In light of these sobering statements we need to take heed to Paul's advice to the Corinthians...

"Test yourselves to see if you are in the faith; examine yourselves! Or do you not recognize this about yourselves, that Jesus Christ is in you-- unless indeed you fail the test?" (2 Cor 13:5)

Ryrie comments that "fail the test" means

"they failed to pass the test and were not members of the household of faith"

Our unbelief will not cancel the faithfulness of God regarding His promises to save eternally or to condemn eternally!

An unbeliever asked one who was genuinely born again

"Are you not afraid you will slip through His fingers?”

To which the believer replied...

“How can I? “I am one of His fingers!”

Geneva Study Bible adds the helpful note that...

"This is a wonderful affirmation of assurance that although we are called to endure and be faithful, salvation does not rest ultimately on our faithfulness, but upon that of Christ." (New Geneva study Bible. Nashville: Thomas Nelson)

It was on that basis of God's faithfulness that the writer of Hebrews admonished,