Therefore (oun) as Eadie says "introduces the inference based on a retrospect."

Edwards explains that...

All mature believers are to have this same mindset. The therefore here also gives good support that Phil 3:10, 11, 12, 13, 14 is basically speaking about being "mature." We see here that one of the marks of being mature in the faith is that our great goal in life is holiness, not happiness. No man can claim to be a mature Christian if this isn't his primary goal! (Reference)

Thus in this section Paul is exhorting those who are spiritually mature ("perfect") to hold the same convictions as he does regarding the need to press on toward the goal of Christlikeness. In the last half of this verse, Paul expresses his recognition that some of the believers will not share his attitude. The implication is that the reason they do not share his attitude is because they are not spiritually mature.

As Steven Cole goes on to explain...

To those who disagree with him, Paul says, “Stay teachable and God will show you where you need to grow” (Sermon)

As many as are perfect - Eadie writes that...

The use of teleios is striking, especially in contrast with teteleiomai in Php 3:12. There, he says—“Not as if I had taken the prize, or were already perfected;” and now he says—“Let as many as are perfect,”...The adjective has plainly a somewhat different sense from the verb. The adjective refers to relative, but the verb to absolute perfection. The one is predicated of him who is in the race and has made some progress; and the other of him who has reached the goal and taken the prize. Perfecti viatores, (Means something like - To do thoroughly as a traveler) says Augustine, nondum perfecti possessores. (Means something like - not yet to do thoroughly as a possessor) The apostle's use of the term sanctions this idea. He elsewhere speaks of two classes in the church —“babes and perfect men.” 1Cor. 2:6; Ep 4:12, 13; He 5:13, 14. The terms nepios (Literally = Not speaking, an infant, a minor) and teleios (mature) are in contrast. See also 1Co 14:20. In the first passage referred to (Php 3:12), the allusion is to respective degrees or attainments in knowledge.

THE
PERFECT

“as many of us as are perfect,” (is a phrase which leaves) it to each of themselves to determine whether the epithet be applicable to him or not. The perfect ones, among whom by the idiom he employs he places himself, are those who have burst the fetters of intellectual and spiritual bondage; who have made some advancement in the divine life; who are acquainted with the higher forms of truth, and are no strangers to the impulses and powers of divine grace; who are the circumcision (Ed: I think he is speaking of heart circumcision as in Ro 2:28, 29-note); who, by the Spirit, worship God; who are conscious of union with Christ, of possessing righteousness through faith in Him, and some measure of conformity to Him, and who cherish through Him the hope of a happy resurrection.

THE
IMPERFECT

And perhaps, if we take in the previous context, the imperfect are those whose minds had not been able so fully to rise above all confidence in the flesh; who still thought circumcision might not be wholly without value (Ed: speaking of physical act); who would scruple (show reluctance on grounds of conscience) to count all such things dead and positive loss (cp Php 3:7, 8-note), but hankered (possessed  a strong or persistent desire) after some of them; and who, in formally renouncing them, secretly or unawares clung to them, and might not distinctly comprehend the freeness, adaptation, and perfection of that righteousness which is through the faith of Christ. They could not be perfect runners in that course which the apostle has traced, for they had not laid aside “every weight.” (cp He 12:1-note) They were entangled at every step (cp 2Ti 2:3, 4-note), and progress was impeded...

The language used by the apostle —hosoi (as many as)—intimates that all were not teleioi (mature) in the Philippian church; the idea of relative progress is therefore involved. Nor does it, as Wiesinger objects, in any way give countenance to self-esteem, for he neither names the teleioi, nor points out precisely in what their perfection consists. On the other hand, he classes himself among the teleioi, and yet he has declared of himself that he was yet not perfected. In fact, the perfect one was only in the way of being perfected; none knew his imperfection so much, or felt it so deeply, and therefore he strove with quenchless ardor to move fleetly onward to the end of the race, and obtain the crown. For one may be perfect in aim, and yet be far from realizing it. The perfection referred to was such a progress as vividly showed defect; such a stage in the race as revealed most painfully the distance lying still in front; such light which, as it grew, served also to enlarge the circle of darkness round about it (Ed: Compare Paul's self assessment as he approached the end of his life! 1Ti 1:15 "foremost" sinner!). (A Commentary on the Greek Text - Online) (Bolding added)

Robertson...

Here the term teleioi means relative perfection, not the absolute perfection so pointedly denied in Php 3:12. Paul here includes himself in the group of spiritual adults (see Heb. 5:13-note).

Perfect (5046) (teleios [word study] from telos = an end, a purpose, an aim, a goal) means complete, mature, fully developed, full grown, brought to its end, finished, wanting nothing necessary to completeness, in good working order. Teleios signifies consummate soundness, includes the idea of being whole. Teleios does not refer to sinlessness but to spiritual maturity. Teleios conveys the ideas of reaching or accomplishing the goal for which we were saved (ultimately Christ- likeness).

NET Bible note...

The adjective perfect comes from the same root as the verb perfected in Php 3:12. Paul may well be employing a wordplay to draw in his opponents. Thus, perfect would then be in quotation marks and Paul would then argue that no one - neither they nor he - is in fact perfect. The thrust of Php 3:1-16 is that human credentials can produce nothing that is pleasing to God (Php 3:1-8). Instead of relying on such, Paul urges his readers to trust God for their righteousness (Php 3:9) rather than their own efforts, and at the same time to press on for the prize that awaits them (Php 3:12, 13, 14). He argues further that perfection is unattainable in this life (Php 3:15), yet the level of maturity that one has reached should not for this reason be abandoned (Php 3:16).  (NET Bible)

Wuest helps understand how this statement can be rationalized with the statement in (Phil 3:12 - note) explaining that in Philippians 3:12...

Paul is speaking of a finished process and absolute spiritual maturity beyond which there is no room for improvement, whereas in Philippians 3:15 he is speaking of relative spiritual maturity where there is room for development and growth. This is clear from the fact that in the former verse (Php 3:12-note) he uses a verb in the perfect tense, whereas in the latter, he uses a noun. Paul therefore exhorts the Philippian saints who are spiritually mature to consider themselves so only in a relative sense, and to remember that there is much room for spiritual growth in their lives. The spiritual maturity spoken of here is as we have seen, not a state of sinlessness or flawlessness, but one of completeness, of a well rounded Christian character, a state opposite to spiritual infancy. (Wuest, K. S. Wuest's Word Studies from the Greek New Testament: Eerdmans or Logos) (Bolding added)

Jamieson explains that those believers who are perfect are...

full grown (no longer “babes”) in the Christian life (Php 3:3-note, “worshipping God in the Spirit, and having no confidence in the flesh”)  1Co 2:6, fully established in things of God. Here, by “perfect,” he means one fully fit for running [Bengel]; knowing and complying with the laws of the course (2Ti 2:5-note). Though “perfect” in this sense, he was not yet “made perfect” (Greek) in the sense intended in Philippians 3:12, namely, “crowned with complete victory,” and having attained absolute perfection.

Adam Clarke writes that...

The word teleioi, perfect, is taken here in the same sense in which it is taken 1 Corinthians 14:20 (Brethren, do not be children in your thinking; yet in evil be babes, but in your thinking be [present imperative = be continually becoming] mature [teleios = attaining to full development as opposed to immaturity]. Be ye perfect-thoroughly instructed, deeply experienced.

1 Corinthians 2:6:- Yet we do speak wisdom among those who are mature (teleios) among those who are fully instructed, adults in Christian knowledge.

Ephesians 4:13 (note) until we all attain to the unity of the faith, and of the knowledge of the Son of God, to a mature man, to the measure of the stature which belongs to the fulness of Christ.

Hebrews 5:14 (note): But solid food is for the mature (teleios), who because of practice have their senses trained to discern good and evil. Here teleios means those who are thoroughly instructed and experienced in Divine things.

Let us therefore, says the apostle, as many as be perfect-as have entered fully into the spirit and design of the Gospel...

Have this attitude - The question is "what attitude" is Paul referring to? We have already mentioned it above, but to reiterate, if we observe the context, we see that Paul has just referred to pursuing the prize of Christlikeness (and all that is implied by this "race", the things he had mentioned in the preceding passages)

Guzik writes that...

Those who are really mature will have this mind. If they do not, Paul trusts that God will reveal the necessity of having it. Paul has great trust in the ability of the Lord to deal with His own people. He doesn't have the attitude that if he doesn't convince them, they will never be convinced.

J Vernon McGee says...

In other words, have the same mind as Paul. Get out on the racetrack with Paul and press on toward the same goal.

MacDonald explains that the mature ("perfect") believers at Philippi

should share Paul’s willingness to suffer and die for Christ and to bend every effort in the quest for likeness to the Lord Jesus. This is the mature view of the Christian faith. Some would call it extreme, radical, or fanatical. But the apostle states that those who are full-grown will see that this is the only sane, logical, reasonable response to the One who shed His life-blood for them on Calvary. (MacDonald, W & Farstad, A. Believer's Bible Commentary: Thomas Nelson or Logos)

Have this attitude - An exhortation to continually (present tense) set your mind on this. Keep on thinking this way, remaining focused on pursuing the goal of Christlikeness and more generally having the mind Paul had described in Philippians 3:7-14 (notes) where he began by explaining the things he had counted as loss for the sake of Christ.

MacArthur adds a slightly different aspect to the interpretation explain that Paul

could be referring to the mature believers who were like-minded with him in this pursuit or he may also have used “mature” here to refer sarcastically to the Judaizers, who thought they had reached perfection.

Have...attitude (5426) (phroneo [word study] from phren = literally the diaphragm and thus that which curbs or restrains. Figuratively, phren is the supposed seat of all mental and emotional activity) refers to the basic orientation, bent, and thought patterns of the mind, rather than to the mind or intellect itself (that is the Greek word nous). Phroneo includes a person’s affections and will as well as his reasoning.  In other words phroneo refers not simply to intellectual activity but also to direction and purpose of heart. Phroneo means to think, set one's mind or heart upon something and denotes the whole action of the affections and will as well as the reason. It describes a process of evaluating a situation and on the basis of our evaluation of adopting an attitude or disposition to act.

Paul is saying to those who are mature to continually (present tense) give careful consideration to what he has just stated. It is also notable that the word phroneo is one of those terms which is difficult to render in English because it includes at once thinking and willing. It expresses not merely an activity of the intellect, but also a movement of the will and thus it is both interest and decision at the same time.

Robertson comments on the present tense...

Present active volitive subjunctive of phroneo. “Let us keep on thinking this,” viz. that we have not yet attained absolute perfection.

Robertson adds that phroneo is in the

Present active volitive (pertaining to volition or relating to the will,  with subjunctive approximating the sense of a command) subjunctive... “Let us keep on thinking this,” viz.  (that is to say) that we have not yet attained absolute perfection." (Robertson, A.  Word Pictures in the New Testament)

Matthew Poole writes that...

from the instance of himself (Paul), imitating Christ, in loving condescension and lowliness of mind, Php 2:3-note, Php 2:5-note, worshipping God in the spirit, and not having confidence in the flesh, Php 3:3-note, in the fellowship of Christ’s sufferings, Php 3:10-note, pressing forward to absolute perfection, he here doth with himself encourage as many rulers and ruled who were settled in the fundamentals of Christianity, and who had made progress in holiness ("as many as are perfect"), to mind that main business of religion...“Be thus minded;” he would have them to be so minded as he himself was, in renouncing all carnal confidence, acknowledging their gradual imperfection, and still to be striving and contending to a fuller measure of holiness, till they come to be consummate in Christ. (Matthew Poole's Commentary on the New Testament)

Spurgeon commenting on Php 3:15 says...

You have seen a man running very fast. How he leans forward, as though he would send his heart before him, and go quicker than his legs can carry him! So did the apostle “press toward the mark for the prize of the high calling of God in Christ Jesus.” (Spurgeon on Philippians)

AND IF IN ANYTHING YOU HAVE A DIFFERENT ATTITUDE GOD WILL REVEAL THAT ALSO TO YOU: kai ei ti heteros phroneite (2PPAI) kai touto o theos humin apokalupsei (3SFAI): (Psalms 25:8,9; Proverbs 2:3-6; 3:5,6; Isaiah 35:8; Luke 11:13; John 7:17; James 1:5)

If (ei) presents, not a hypothetical case but a fulfilled condition or one that is assumed to be true. That is, it is true that some of the Philippians had a different attitude.

Eadie...

The conjunction ei is followed by the indicative implying condition, simply and purely, “if, as may be the case.” Ti (pronoun indefinite accusative neuter singular - Tis = a reference to someone or something indefinite, anyone, anything [the most appropriate meaning in context]; someone) is the accusative of reference, and that reference is certainly not to any essential points of doctrine, but to aspects of truth or elements of spiritual experience, which the apostle has been presenting. They might not see those relations of truth so clearly as the apostle, and their convictions might not be so profound, or their progress so rapid and uniform. (A Commentary on the Greek Text - Online)

Different (2088) (heteros) is an adverb which is used only here in the NT and means differently (in a different manner, not identically), otherwise.

And if in anything you have a different attitude - In other words if you don't agree with what Paul has just stated about pursuing Christlikeness.

Eadie adds...

the true idea is brought out simply by the implied contrast ("you have a different attitude"). This difference must be wrong, so far as it does not correspond with the apostle's mind, and the amount of error is just in proportion to the amount of difference; and that it is wrong, is also shown from the apostle's expectation, that God would set them right ("God will reveal that also to you"). The revelation which the apostle promises they should enjoy, had for its purpose to remove such disagreement, and bring them to his mind (cp 1Cor 4:16, 11:1, 1Th 1:6-note). (A Commentary on the Greek Text - Online)

As alluded to above MacArthur raises the possibility that the different attitude was in fact the attitude of some that they had arrived at perfection, which may have also been a jab at Judaizers in the midst of the believers (cp the context - "enemies of the cross of Christ" - Php 3:18-note).

Jamieson takes this latter view writing that those with a different attitude refer to those...

having too high an opinion of yourselves as to your attainment of Christian perfection. “He who thinks that he has attained everything, hath nothing” [Chrysostom]. Probably, too, he refers to those who were tempted to think to attain to perfection by the law (Gal 3:3): who needed the warning (Php 3:2-note), “Beware of the concision (the circumcision),” though on account of their former piety, Paul hopes confidently (as in Gal 5:10) that God will reveal the path of right-mindedness to them. Paul taught externally God “reveals” the truth internally by His Spirit (Mt 11:25; 16:17; 1Co 3:6).(Philippians Commentary)

God will reveal - Paul is saying if you don't agree, the only thing he can do is turn the case over to God.

Eadie commenting on revelation to the saints at Philippi says that...

Such spiritual enlightenment was frequent in those times, when the written oracles of the New Testament were not in circulation, and indeed is needed at all times, to give the mind a just and abiding perception of the truth. Ps 25:9; 1John 2:20. It is plain, therefore, that the difference of view was not some wilful and wicked misconception, or some wretched prejudice, adhered to with inveterate or malignant obstinacy. It was rather some truth not fully seen in all its bearings—some principle not so perceived as to be carried out in all its details and consequences—some department of duty which they might apprehend rather than appreciate — or some state of mind which they might admire in the apostle, but did not really covet for themselves. The apostle throws his own teaching into the shade, and ascribes the coming enlightenment to God. He might have taught them the necessary lesson, or it might be found in the previous details of the chapter, or Epaphroditus on returning might be commissioned to explain and enforce it; yet all might be insufficient, and therefore the work is taken out of man's hand, and the needed insight is declared to be the gift of the Father of Lights (Jas 1:17-note).

Reveal (601) (apokalupto from apó = from + kalúpto = cover, conceal, English = apocalypse  - see study of apokalupsis English = apocalypse) literally means to remove the cover from and so the idea is to remove that which conceals something. Almost all of the NT uses have a figurative use, especially to some aspect of spiritual truth that was heretofore hidden but now has the "lid removed" so that it can be seen (understood).

Comment: A T Robertson says that "It is a revelation from God, this God kind of righteousness, that man unaided could never have conceived or still less attained. In these words we have Paul’s statement in his own way of the theme of the Epistle, the content of the gospel as Paul understands it. Every word is important."

Vincent adds "Righteousness as an attribute of God was revealed before the Gospel. Righteousness in this sense is a matter of special revelation through the Gospel. The present tense describes the Gospel in its continuous proclamation: is being revealed."

1Corinthians 2:10 For to us God revealed them (What? see 1Cor 2:9) through the Spirit; for the Spirit searches all things, even the depths of God.

Comment: A T Robertson says that "Paul explains why this is no longer hidden, “for God revealed unto us” the wonders of grace pictured in verse 9. We do not have to wait for heaven to see them. Hence we can utter those things hidden from the eye, the ear, the heart of man."

2Th 2:3 Let no one in any way deceive you, for it (the Day of the Lord will be #3) will not come unless the apostasy comes first (#1), and the man of lawlessness (#2) is revealed, the son of destruction (the Antichrist)...6 And you know what restrains him (Antichrist) now, so that in his time (kairos = a specific segment of time determined by God Who Alone is sovereign over time and history) he may be revealed...8 And then that lawless one (Antichrist) will be revealed whom the Lord will slay with the breath of His mouth and bring to an end by the appearance of His coming;

1Pe 1:5-note (cp Ro 8:18-note above, cp 1Pe 5:1-note) who (believers 1Pe 1:3-note) are protected by the power of God through faith for a salvation ready to be revealed in the last time. (When? What? When we see Christ in glory and are like Him [glorification], then our salvation will be completed.)

Genesis 8:13 (Literal) Now it came about in the six hundred and first year, in the first month, on the first of the month, the water was dried up from the earth. Then Noah removed the covering (Lxx = apokalupto) of the ark, and looked, and behold, the surface of the ground was dried up.

Numbers 22:31 (Figurative - spiritual truth revealed) Then the Lord opened (Lxx = apokalupto) the eyes of Balaam, and he saw the angel of the Lord standing in the way with his drawn sword in his hand; and he bowed all the way to the ground.

Ruth 3:4 (Literal) “It shall be when he lies down, that you shall notice the place where he lies, and you shall go and uncover his feet and lie down; then he will tell you what you shall do.”

1 Samuel 3:7 (Figurative - spiritual truth revealed) Now Samuel did not yet know the Lord, nor had the word of the Lord yet been revealed (Lxx = apokalupto)  to him.

Psalm 98:2 (Figurative - spiritual truth revealed)  The Lord has made known His salvation; He has revealed (Lxx = apokalupto) His righteousness (Jesus - Jer 23:6, 2Pe 1:1) in the sight of the nations.

Psalm 119:18 (Figurative - spiritual truth revealed) Open (aorist imperative; Lxx = apokalupto) my eyes, that I may behold wonderful things from Your law.

Daniel 2:28 (Figurative - spiritual truth revealed) However, there is a God in heaven Who reveals (Lxx = apokalupto) mysteries, and He has made known to King Nebuchadnezzar what will take place in the latter days. This was your dream and the visions in your mind while on your bed.

Lamentations 2:14 (Figurative - spiritual truth revealed) Your prophets have seen for you false and foolish visions and they have not exposed (Lxx = apokalupto) your iniquity so as to restore you from captivity, but they have seen for you false and misleading oracles.

Comment: God's prophets (see Amos 3:7 below) must speak God's Word as one of the functions of His Word of truth is to take the lid off the lies and iniquity of the hearers. Why do they need to hear His Word of Truth and Light? They are otherwise in spiritual darkness and are deceived by their sin [see He 3:13].

Amos 3:7 (Figurative - spiritual truth revealed) Surely the Lord God does nothing unless He reveals (Lxx = apokalupto) His secret counsel to His servants the prophets.

The psalmist David echoes Paul's words about the Lord's desire and power to reveal His truth reminding us that...

Good and upright is the Lord. Therefore He instructs sinners in the way. He leads the humble in justice, and He teaches the humble His way. (Who is able to learn spiritual truth? See C H Spurgeon's thoughts. Do you have a teachable heart? Do you tremble at His Word? Isa 66:2, 5, Pr 28:14, Ps 119:161, Ezra 9:4, 10:3) (Ps 25:8, 9-note)

Solomon echoes this truth and places some of the responsibility on us writing...

For if you cry for discernment, lift your voice for understanding; If you seek her as silver, and search for her as for hidden treasures, then you will discern the fear of the LORD, and discover the knowledge of God. For the LORD (Jehovah) gives wisdom. From His mouth come knowledge and understanding. (Pr 2:3, 4, 5, 6 - see Bridges - A Commentary on Proverbs)

Trust in the Lord with all your heart and do not lean on your own understanding. In all your ways acknowledge Him, and He will make your paths straight. (Pr 3:5,6 -see Bridges - A Commentary on Proverbs)

And James reminds us that...

if any of you lacks wisdom, let him ask of God, who gives to all generously and without reproach, and it will be given to him. (Jas 1:5-note, see the "condition" the assures fulfillment of this promise = Jas 1:6, 7, 8-note, cp Jas 2:2b, Mt 7:7, 8-note)

Remember that as our Lord so clearly taught, a critical dynamic in truly learning spiritual truth is faithfully doing spiritual truth (obeying the truth your Teacher, the Spirit, illumines, cp Jn 14:26)

If anyone is willing to do (present tense = as one's lifestyle = direction not perfection!) His will (most clearly revealed in His Word of truth), he will know (ginosko = by experience) of the teaching (didache), whether it is of God or whether I speak from Myself. (John 7:17)

As Guzik puts it...

Paul has great trust in the ability of the Lord to deal with His own people. He doesn’t have the attitude that if he doesn’t convince them, they will never be convinced. (Philippians 3 Commentary )

Ryrie paraphrases it...

If you don't agree, God will give you light on the subject. (The Ryrie Study Bible)

MacDonald comments that...

Paul realizes that not all will agree with him in adopting such a dangerous philosophy. But he expresses the confidence that if a person is really willing to know the truth of the matter, God will reveal it to him. The reason we have such an easy-going, complacent Christianity today is because we do not want to know the truth; we are not willing to obey the demands of ideal Christianity. God is willing to show the truth to those who are willing to follow it.

Edwards explains that...

If their minds were set on anything else, any other goal in life, God would reveal it to them. It would seem that this revelation must come through the convicting ministry of the Holy Spirit. It is comforting to know that when we get off the track God will point it out to us so that we can get back on (Reference)

MacArthur explains that...

Those who refuse to heed Paul’s message will hear that same message from God. He will correct them through His Word, His Spirit, or through chastening. God will do whatever it takes to make believers recognize their need to pursue the prize of Christlikeness. He will also provide the resources they need to do that (see note 2 Peter 1:3). (MacArthur, J. Philippians. Chicago: Moody Press or Logos)

Barnes explains that God is able to...

However (nevertheless) - “even though there be those who are otherwise minded” (Eadie)

However (plen) means more than, over and above, hence, besides. In the present verse Paul is saying now let me tell you one more thing. Plen is a word that is often used at the end of a paragraph to express a final thought.

To paraphrase Paul is saying

One more thing, by the way, let us keep living by that same to which we have attained.

Vincent translates it

Notwithstanding the minor points in which you may be otherwise minded. (Vincent, M. R. . Word Studies in the New Testament. Vol. 3, Page 1-451)

Jamieson writes that...

The expectation of a new revelation is not to make you less careful in walking according to whatever degree of knowledge of divine things and perfection you have already attained. God makes further revelations to those who walk up to the revelations they already have (Ho 6:3).

Keep living by the (same) standard (4748) (stoicheo [word study] from stoichos = row, line, rank; see word study of stoicheion = elements, basic foundational things like letters of the alphabet) is literally to walk in line, walk in a straight line, proceed in a row, to follow in someone’s footsteps. To keep in rank and file. To march in in file or in battle order. The word was used for movement in a definite line, as in military formation or dancing.

We have attained (5348) (phthano) originally meant to precede someone, to come before or to anticipate (as used in 1Th 4:15-note). Over time phthano begin to lose the idea of priority and to mean simply to come to or to arrive at. The idea is to come to a particular state or to arrive at a goal and so to attain it. In Mt 12:28 it means to happen to someone.

Phthano pictures progress along a road to a certain point. Paul is thinking of the Philippian saint's progress along the path of Christ-likeness. His idea is, “so far as we have come.”

TDNT says that the...

The LXX uses phthano for a Hebrew term meaning “to show oneself ready,” “to do quickly,” “to accomplish.” In the absolute the word means “to attain,” “to reach,” “to come to.” ... In Philo we find the weaker sense “to attain to” or “to come before.” “To come before” is the usual sense in Josephus. (Kittel, G., Friedrich, G., & Bromiley, G. W.  Theological Dictionary of the New Testament. Eerdmans)

Phthano - 7x in 7v - Mt 12:28; Luke 11:20; Ro 9:31; 2Cor 10:14; Phil 3:16; 1Th 2:16; 4:15. NAS = arrive(1), attained(1), come(3), first to come(1), precede(1).

Phthano - 20x in the Septuagint (LXX) - Jdg 20:34, 42; 2Sa 20:13; 1Kgs 12:18; 2Chr 28:9; Ezra 3:1; Neh 7:73; Eccl 8:14; 12:1; Song 2:12; Da 4:11, 20, 22, 24, 28; 6:24; 7:13, 22; 8:7; 12:12

Vincent explains that Paul is saying in essence...

Whatever real Christian and moral attainment you may have made, let that serve as a rule for your further advance. The character of this standard of attainment is illustrated by the words in Philippians 3:15, be thus minded (KJV), and by those in Php 3:17 (note), as ye have us for an example. The individual variations are not considered. He regards rather the collective development, and assumes the essentials of Christian attainment on the part of his readers.

Richards writes that...

In Php 3:11-16, Paul looks again at the idea of spiritual attainment. He himself has turned his back on his own considerable accomplishments under law. He has tossed them aside and considers them worthless. His goal now is simply to be found in Christ and so to "attain to the resurrection from the dead." (Php 3:10-note) This expression does not refer to the coming physical resurrection but to Paul's present experience of a power for righteous living that can be found only by faith and only as Jesus shares His own resurrection life with the believer (cp Php 3:9-note; Ro 6:8-note, Ro 6:13-note). This experience of power comes as we seek to follow Jesus and put into daily practice whatever level of understanding and maturity we may arrive at (phthano).

The picture that emerges as we connect these passages is an exciting one. God does have a high calling for Christians. But we attain it, not by self-reliant attempts to live by the law, but rather by humble commitment of ourselves to Jesus, asking and believing by faith that he will give us the power to follow him. (Richards, L O: Expository Dictionary of Bible Words: Regency)

Eadie commenting on this verse writes that...

The spirit of the warning or injunction is, that knowledge already enjoyed and proved in a spiritual race, should not lie dormant because it is defective. It needed not so much to be rectified, as to be supplemented. Therefore, as far as you have its guidance, take it. Walk up to the light you have, and you will get more. Walk with me so far as you discern the common path, and at the point of divergence God shall rightly direct you as to the subsequent course. He who employs what he has, prepares himself for further gifts. When the morning bursts suddenly on one wakened out of sleep, it dazzles and pains him; but to him who on his journey has blessed the dawn, and walked by its glimmer, the solar radiance brings with it a gradual and cheering influence.  (A Commentary on the Greek Text - Online)