THEREFORE: oun

"Therefore" refers back to [v10-12] in which Paul reminds his readers that God alone is qualified and has the authority to judge the minds and hearts of His people, who will all stand before His judgment seat (v10) and give account of themselves to Him (v12 cf. 2Co 5:10). Judgment is God’s exclusive prerogative (cp Ro 12:19).

LET US NOT JUDGE ONE ANOTHER ANYMORE: Meketi oun allelous krinomen (1PPAS): [Mt 7:1-5 Ja 2:4 4:11]

"Let us no longer have the habit of criticizing one another."

This statement summarizes what we have covered so far: we are not to judge one another which is in harmony with what the Jesus instructed [Mt 7:1] It is the unloving attitude of contemptuous superiority by strong believers and the equally unloving attitude of self righteousness by weak believers (v3) by which they judge one another. From Paul’s day to ours, those wrongful judgments have been major causes of disrespect, disharmony, and disunity in the church.

Our Daily Bread has the following devotional entitled "Unfairly Judged"

We sometimes criticize others unfairly. We don’t know all their circumstances, nor their motives. Only God, who is aware of all the facts, is able to judge people righteously.

John Wesley told of a man he had little respect for because he considered him to be miserly and covetous. One day when this person contributed only a small gift to a worthy charity, Wesley openly criticized him. After the incident, the man went to Wesley privately and told him he had been living on parsnips and water for several weeks. He explained that before his conversion, he had run up many bills. Now, by skimping on everything and buying nothing for himself he was paying off his creditors one by one.

“Christ has made me an honest man,” he said, “and so with all these debts to pay, I can give only a few offerings above my tithe. I must settle up with my worldly neighbors and show them what the grace of God can do in the heart of a man who was once dishonest.”

Wesley then apologized to the man and asked his forgiveness. (Our Daily Bread)

BUT RATHER DETERMINE (judge) THIS: alla touto krinate (2PAAM) mallon:

Aorist Imperative conveys the sense of taking a definite action ("Do it now! Just do it!"), even a sense of "urgency": The idea is "Do this & do it now! Do it effectively!" Check yourself out first -- Are you pushing your Christian liberty so hard, are you insisting on your rights in certain areas, and your freedom to indulge in something, that you are upsetting others and forcing them to act beyond their own conscience (stumbled or snared)? That is what you ought to judge. What is the effect upon others of your attitudes about some of these things?

We should determine (judge) that we will never do anything to hinder a brother in his spiritual progress. None of these nonessential matters is important enough for us to cause a brother to stumble or to fall.
           
The Greek verb KRINO (G2919) (see 14 uses in Romans) is used twice in this verse, but with a slightly different connotation. In the first use of "krino" "let us not judge one another" the verb carries the idea of condemnation, as it does in (Ro 14:3, Ro 14:4, Ro 14:10). But in the following phrase, the same verb is translated determine, which refers to making a decision. Those two connotations are also found in the English word judge. “Being judgmental” carries the negative idea of denunciation, whereas “using your best judgment” refers to making a careful decision, with no negative connotation. Paul’s play on words demands that we should never be judgmental of fellow believers but instead should use our best judgment to help them.    

NOT TO PUT AN OBSTACLE: to me tithenai (PAN) proskomma:

Obstacle (4348) (proskomma from prós = to, against + kópto = cut, strike) can describe literal or figurative stumbling. It is something a person trips over. Thus proskomma can be an obstacle in the way which if one strikes his foot against he stumbles or falls or figuratively it can describe that over which a soul stumbles i.e. by which is caused to sin or which causes an occasion of apostasy. It is also used  figuratively, to describe a cause of falling or an occasion of sinning (Ro 14:13, 20; 1 Cor. 8:9; Sept.: Ex. 23:33; 34:12).

Barclay writes that...

proskomma, means 'a barrier', 'a hindrance', 'a road-block'. It is the word that would be used for a tree that has been felled and laid across a road to block it. We must never do or allow anything which would be a road-block on the way to goodness. (William Barclay. New Testament Words)

In this verse proskomma speaks of the spiritual hindrance to another caused by a selfish use of liberty or alternatively our tendency to set up a list of do's and don'ts. Either way could cause the other person to stub his spiritual toe!. Paul says do not do this.

OR A STUMBLING BLOCK IN A BROTHER'S WAY: to me tithenai (PAN) proskomma to adelpho e skandalon:

Offense (4625) (skandalon from a root meaning jump up, snap shut) (Click in depth study of skandalon) was originally the piece of wood that kept open a trap for animals. Outside the Bible it is not used metaphorically, though its derivative skandalethron (e.g. a trap set through questions) is so used. The English word scandal is derived from the noun via the Lat. scandalum.

Thus skandalon was literally, that movable part of a trap on which the bait was laid, and when touched caused the trap to close on its prey. Skandalon thus came to mean any entanglement of the foot. Figuratively, as used most often in Scripture, skandalon refers to any person or thing by which one is drawn into error or sin. (but see more detailed notes below)

The use of alcohol is an example of a stronger brother who in the process of using his liberty regarding alcohol intake potentially sets a stumbling block in his weaker brother's way. One must never underestimate the potentially detrimental effect this can have on a former alcoholic. Our drinking, even in moderation, could easily place a stumbling block in that brother’s way and cause him to fall back into his former addiction.

(Trench) explains "stumbling block" or skandalon as "literally, that part of a trap on which the bait was laid, when touched caused the trap to close on its prey came to mean any entanglement of the foot." When the bait touches trap > triggered and closes shut on its victim. That's a picture of sin = looks alluring, but touched, it captures its unsuspecting prey.

Vines Dictionary has a helpful, illustrative discussion:

"Skandalon  originally was the name of the part of a trap to which the bait is attached, hence, the trap or snare itself, (in the picture of the trap note the centrally located "pitchfork" shaped trigger where bait is to be placed & which when stepped on releases the two side bars which entrap the victim in a vise like grip -- keep this picture in mind as you meditate on the uses of this word in Ro 14:13 & in the other NT passages) as in Ro 11:9, ‘stumblingblock,’ quoted from Ps 69:22, and in Re 2:14, for Balaam’s device was rather a trap for Israel than a stumblingblock to them, and in Mt 16:23, for in Peter’s words the Lord perceived a snare laid for Him by Satan. “

In NT Skandalon is always used metaphorically, and ordinarily of anything that arouses prejudice, or becomes a hindrance to others, or causes them to fall by the way. Sometimes the hindrance is in itself good, and those stumbled by it are the wicked.”* Thus it is used (a) of Christ in Ro 9:33, “(a rock) of offense”; so 1Pe 2:8; 1Co 1:23 (kjv and rv, “stumblingblock”), and of His cross, Ga 5:11; of the “table” provided by God for Israel, Ro 11:9; (b) of that which is evil, eg, Mt 13:41, rv, “things that cause stumbling” (kjv, “things that offend”), lit., “all stumblingblocks”; Mt 18:7, rv, “occasions of stumbling” and “occasion”; Lu 17:1; Ro 14:13, rv, “an occasion of falling” (kjv, “an occasion to fall”), said of such a use of Christian liberty as proves a hindrance to another; Ro 16:17, rv, “occasions of stumbling,” said of the teaching of things contrary to sound doctrine; 1Jn 2:10, “occasion of stumbling,” of the absence of this in the case of one who loves his brother and thereby abides in the light.

Love, then, is the best safeguard against the woes pronounced by the Lord upon those who cause others to stumble. Cf.. In Ho 4:17, the Septuagint is translated: “Ephraim partaking with idols hath laid stumblingblocks in his own path.” (metochos eidolon Ephraim etheken (3SAAI) heauto skandala)

Our Daily Bread has the following devotional entitled "Living With Others in View"...

I KNOW AND AM CONVINCED (have conviction) IN THE LORD JESUS THAT NOTHING IS UNCLEAN IN ITSELF :oida (1SRAI) kai pepeismai (1SRPI) en kurio Iesou hoti ouden koinon di heautou: (1Ti 4:4-5)

 What Paul is saying in essence is "Don't violate your conscience."
           
When Paul says here that there is nothing unclean of itself, we must realize that he is speaking only of these indifferent matters. There are plenty of things in life that are unclean, such as pornography, suggestive jokes, PG & higher rated movies & every form of immorality. Paul’s statement must be understood in the light of the context. Christians do not contact ceremonial defilement by eating foods which the Law of Moses branded unclean.
           
Having been a Pharisee, a member of those well known for majoring on the minors, Paul doubtless had been extremely careful about what he ate and did not eat. But he now understood with absolute certainty the truth which the Lord declared to Peter three times in a vision: “What God has cleansed, no longer consider unholy” (Ac10:15). That divine cleansing referred directly to the multitude of animals Peter was commanded to eat that were ceremonially unclean ac- cording to Mosaic law (Ac10:12-13). Indirectly, and in an even more important way, it referred to God’s full and impartial acceptance of believing Gentiles into the church (Ac10:28, 34).Jesus declared that “there is nothing outside the man which going into him can defile him” (Mk7:15). The strong Christian is therefore entirely right in his conviction that he is at liberty to enjoy anything the Lord does not declare to be sinful. The weak Christian, on the other hand, is wrong in his understanding about some of those things. But he is not wrong in the sense of being heretical or immoral. He is wrong in the sense of not having complete and mature understanding, which causes his conscience to be unnecessarily sensitive.
           
Morris writes that...

 "To the believer, saved by grace through faith in Christ and His provision of full forgiveness and justification, all things are legal. Note such assurances as [Titu1:15 1Co10:23 Ga5:1,4]. Nevertheless, since he should now desire to live and die as unto the Lord (Ro14:8), this should clearly affect all his behavior and make him very different from those yet unsaved."

Stedman adds that...

"As one who is in the Lord Jesus," that is, as one speaking as a Christian. What Paul really says is, "As one who has been taught by the Lord Jesus, no food is unclean in itself." The Lord Jesus did say that. It was he who said, "No food is unclean." He does not mean that all foods are good for you; some foods are not; some things you can eat are highly poisonous. Jesus does not mean that everything is all right to take in; he means that there is no moral question about food. It is never wrong, morally, to eat what your body may enjoy. Jesus taught that himself, and Paul says, "That is enough for me. That sets me free." But that is not the only problem involved. The conscience needs to be trained by this new insight into liberty. One person's conscience may move much slower than another's, therefore, we are to adjust to one another's needs along this line.

Wiersbe says...

What something does to a person determines its quality. One man may be able to read certain books and not be bothered by them, while a weaker Christian reading the same books might be tempted to sin. But the issue is not, “How does it affect me?” so much as, “If I do this, how will it affect my brother?” Will it make him stumble? Will it grieve him or even destroy him by encouraging him to sin? Is it really worth it to harm a brother just so I can enjoy some food? No!"

BUT TO HIM WHO THINKS ANYTHING TO BE UNCLEAN, TO HIM IT IS UNCLEAN: di heautou, ei me to logizomeno (PMPMSD) ti koinon einai (PAN) ekeino koinon:

if someone believes it is wrong, then for that person it is wrong. Paul is saying essentially "Don't violate your conscience." If a weak brother thinks it is wrong for him to eat pork, for example, then it is wrong. To eat it would be to violate his God-given conscience.
           
"Thinks" = logizomai (G3049) (click Romans  to review the 19/41 NT uses)  = think about something in a detailed and logical manner = drawing of inferences or conclusions through the use of reason. This was a common secular term used in bookkeeping to describe an entry in an accounting ledger. The purpose of the entry was to make a permanent record that could be consulted whenever needed. In sum logizomai means to draw a logical conclusion from a given set of facts, as in Romans 6:11 where one is commanded to draw the conclusion (from Romans 6:1-10) that we are "dead to sin, but alive to God in Christ Jesus". In the present context it pictures a weaker brother looking at the issues involved and arriving at the conclusion that the issues are "unclean". It is easy to see how this brother could become very judgmental of the stronger brother who considers the same facts but concludes they are not permissible to indulge in.
           
"Unclean" = koinos (G2839) = common, defiled, unclean, unholy, profane.  "Koinos" was a technical term to express those customs and habits which, although "common" to he world, were forbidden to the pious Jew (see similar meaning in Mk7:2, Mk7:5, Ac 10:14, Ac 10:15, Ac 10:28, Ac 11:8, Ac 11:9, Re 21:27).
           
For various reasons, there are certain things that we all know are not sinful but that we do not feel comfortable in doing or even being near. And as long as we feel discomfort about any such thing, we should avoid doing it—even if it would not cause offense to other believers. If we ourselves consider anything to be unclean, then to us it is unclean.
           
Stedman comment that...

FOR IF BECAUSE OF FOOD YOUR BROTHER IS HURT : ei gar dia broma o adelphos sou lupeitai (3SPPI): (cp 1Co8:9-11)

"Hurt" (G3076) (Lupeo)  (cf 1Th 4:13, 1Pe 1:6, 6x in Matt, 7x in 2Cor) has the basic meaning of causing pain, distress, or grief & is used by John to describe Peter’s reaction when Jesus asked “him the third time, ‘Simon, son of John, do you love Me?”’and “Peter was grieved” (Jn21:17). It is even used of the Holy Spirit, who is grieved when we sin (Eph 4:30).       
           
It is wrong to hurt our brother over such trivial matters. It is not loving to force people to move at your pace. To refuse to indulge a freedom that you have for the sake of someone else, to adjust to their pace, is surely one of the clearest and truest exercises of Christian love. Is there some non-essential ("food") I need to give up for the higher interest of my brother (that's what agape love does)?
           
William MacDonald notes that...

"When I sit down to eat with a weak brother, should I insist on my legitimate right to eat Crab Louis or Lobster Thermidor, even if I know he thinks it is wrong? If I do, I am not acting in love, because love thinks of others, not of self. Love foregoes its legitimate rights in order to promote the welfare of a brother. A dish of food isn’t as important as the spiritual well-being of one for whom Christ died. And yet if I selfishly parade my rights in these matters, I can do irreparable damage in the life of a weak brother. It isn’t worth it when you remember that his soul was redeemed at such a towering cost—the precious blood of the Lamb."

YOU ARE NO LONGER WALKING ACCORDING TO LOVE: ouketi kata agapen peripateis (2SPAI):

What is walking in love? Not all believers are mature, and love demands that the mature members of the family defer to the immature. Love (agape) protects people and gives them a chance to grow up. People may be (will be!) difficult, but we are to accept them in love for the Lord’s sake.

"Walking" is peripateo (4043) is used 4 times in Romans (Ro 6:4,Ro 8:4, Ro 13:13) and literally means "to tread all around" & figuratively refers to living or passing one’s life, "signifying the whole round of the activities of the individual life, whether of the unregenerate, (Ep4:17) or of the believer (1Co 7:17; Col 2:6)".

I like Ray Stedman's comment on [Col3:1-17] concerning "walk" (peripateo):

"That (referring to the truth in Col3:1-4) is the true basis for living a Christian life. Scripture calls it "walking with the Lord." I like that figure because a walk, of course, merely consists of two simple steps, repeated over and over again. It is not a complicated thing. In the same way, the Christian life is a matter of taking two steps, one step after another. Then you are beginning to walk. Those two steps follow in this passage. Paul describes them as, "Put off the old man," and "put on the new." Then repeat them. That is all. Keep walking through every day like that. That is how Scripture exhorts us to live."

In its figurative sense, peripateo refers to one's habitual way of life, to their life-style. Luke describes Zacharias & Elizabeth, the parents of John the Baptist, as being “righteous in the sight of God, walking blamelessly in all the commandments and requirements of the Lord” (Lu1:6).

Paul counseled the Ephesian believers to “walk no longer just as the Gentiles also walk, in the futility of their mind” (Ep4:17).

John declares that, “if we walk in the light as [God] Himself is in the light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin” (1Jn1:7).

Strong believers (15:1) must not insist on their liberty in the presence of those whose consciences would be offended. if a "weaker" Christian is distressed by what you eat, you are not acting in love if you eat it. Stott says, “Love never disregards weak consciences”. To the one who loves, a weak brother’s spiritual well-being is always more important than indulging the right to eat whatever one likes.
           
A weak Christian (14:1-3) can be hurt or distressed from watching another Christian say or do something he considers sinful. The hurt is deeper if the offending believer is admired and respected by the weaker one. A weak Christian also can be hurt when, by word or example, he is led by a stronger brother to go against the convictions of his own conscience. That is by far the greater offense. Being upset over what another Christian does can certainly hurt, but that hurt is not nearly so severe and damaging as the hurt of a believer’s conscience over what he himself has done. He suffers feelings of guilt, and forfeits much of his peace of mind, his joy, his witness, and perhaps even his assurance of salvation. A Christian whose careless use of his liberty causes such hurt to other believers is no longer walking according to love.

DO NOT DESTROY WITH YOUR FOOD HIM FOR WHOM CHRIST DIED: me to bromati sou ekeinon apollue (2SPAM) huper ou Christos apethanen (3SAAI):  (1Co8:11 "For through your knowledge he who is weak is ruined [apollumi], the brother for whose sake Christ died")

The Greek combination of a negative ("me" = not) plus the present imperative (command) can be translated "stop destroying" (indicating that this  was already being practiced by believers in Rome) your brother over these non-essential issues of what you eat, etc. To act this way is to practice love WITH hypocrisy (Ro 12:9).

This is NOT being "devoted to one another in brotherly love" and is NOT giving "preference to one another in honor" (Ro 12:10).

It is NOT owing "nothing to anyone except to love one another" for clearly "Love does no wrong to a neighbor" (Ro 13:10).

In sum, this type of behavior is NOT walking according to love. If we are to live a life of consideration for our neighbor then we must learn that even though there are things we feel we biblically may do, many of those same things, for the sake of the body of Christ, we should not do. Agape love lays down its rights, seeking the highest good of the other person.
          
(McGee) "Since Christ was willing to die for that weak brother (Ro 5:8, Jn15:13, Isa 53:6, 1 Pet 3:18, 1 Jn 3:16 4:9,10), certainly we ought to be willing to refrain from eating something or doing something that would hurt him in his Christian walk."          

To destroy is apollumi (G622) & is derived from apo [G575] away from + olethros [G3639] state of utter ruin.

Apollumi pertains to destruction but not annihilation & basically has to do with that which is ruined and is no longer usable for its intended purpose. It does not refer to the loss of being, but of well-being. The KJV sometimes translates it "damnation" but in the context of Ro 14 apollumi does not mean that one brother can cause the "damnation" of another brother to the lake of fire, but it does indicate that one can seriously derail & ruin the offended brother's spiritual growth "in the grace and knowledge of our Lord and Savior Jesus Christ" (2 Pet 3:18,  1Cor8:11,  Ro14:20).

Jesus used apollumi with this connotation in (Mt18:14) referring to nonpermanent ruin or loss. When Jesus said, “It is not the will of your Father who is in heaven that one of these little ones perish [apollumi]” (Mt18:14), the context makes clear that “these little ones” are believers. They have been “converted and become like children” (Mt18:3) and “believe in Me” (Mt18:6). Jesus was not concerned about their loss of salvation but about their loss of spiritual well being, which, although not an eternal loss, is a injury the Lord considers to be extremely grave.

A brother's "ruin" is a serious consequence that I fear most believer's (including myself) do not fully comprehend.

Paul does not want the church to underestimate the significance of the non-essentials in the overall spiritual vitality of the body of Christ, for "if one member suffers, all the members suffer" (1Co12:26) and on a given day yet future we will ALL (each one individually) give an accounting of how we dealt with our brethren regarding  the "externals" (Rom 14:10,12, 2 Cor 5:10, Matt 12:36; 16:27; 1 Pet 4:5).

John gives us sage advice

"And now, little children, abide in Him, so that when He appears, we may have confidence and not shrink away from Him in shame at His coming....We know that, when He appears, we shall be like Him, because we shall see Him just as He is. And everyone who has this hope fixed on Him purifies himself, just as He is pure." (1 Joh 2:28, 3:2-3)