If it be possible, etc. Peaceableness and a life so ordered as to render us beloved by all, is no common gift in a Christian. If we desire to attain this, we must not only be endued with perfect uprightness, but also with very courteous and kind manners, which may not only conciliate the just and the good, but produce also a favorable impression on the hearts of the ungodly. But here two cautions must be stated: We are not to seek to be in such esteem as to refuse to undergo the hatred of any for Christ, whenever it may be necessary. And indeed we see that there are some who, though they render themselves amicable to all by the sweetness of their manners and peaceableness of their minds, are yet hated even by their nearest connections on account of the gospel. The second caution is, -- that courteousness should not degenerate into compliance, so as to lead us to flatter the vices of men for the sake of preserving peace. Since then it cannot always be, that we can have peace with all men, he has annexed two particulars by way of exception, If it be possible, and, as far as you can. But we are to conclude from what piety and love require, that we are not to violate peace, except when constrained by either of these two things. For we ought, for the sake of cherishing peace, to bear many things, to pardon offenses, and kindly to remit the full rigor of the law; and yet in such a way, that we may be prepared, whenever necessity requires, to fight courageously: for it is impossible that the soldiers of Christ should have perpetual peace with the world, whose prince is Satan.

If it be possible - If it can be done. This expression implies that it could not always be done. Still it should be an object of desire; and we should endeavor to obtain it.
As much as lieth in you - This implies two things:
(1) We are to do our utmost endeavors to preserve peace, and to appease the anger and malice of others.
(2) we are not to "begin" or to "originate" a quarrel.
So far as "we" are concerned, we are to seek peace. But then it does not always depend on us. Others may oppose and persecute us; they will hate religion, and may slander, revile, and otherwise injure us; or they may commence an assault on our persons or property. For "their" assaults we are not answerable; but we are answerable for our conduct toward them; and on no occasion are we to commence a warfare with them. It may not be "possible" to prevent their injuring and opposing us; but it is possible not to begin a contention with them; and "when they" have commenced a strife, to seek peace, and to evince a Christian spirit. This command doubtless extends to everything connected with strife; and means that we are not to "provoke" them to controversy, or to prolong it when it is commenced; see Psalm 34:14; Matthew 5:9, Matthew 5:39-41; Hebrews 12:14. If all Christians would follow this command, if they would never "provoke" to controversy, if they would injure no man by slander or by unfair dealing, if they would compel none to prosecute them in law by lack of punctuality in payment of debts or honesty in business, if they would do nothing to irritate, or to prolong a controversy when it is commenced, it would put an end to no small part of the strife that exists in the world.

If it be possible - To live in a state of peace with one's neighbors, friends, and even family, is often very difficult. But the man who loves God must labor after this, for it is indispensably necessary even for his own sake. A man cannot have broils and misunderstandings with others, without having his own peace very materially disturbed: he must, to be happy, be at peace with all men, whether they will be at peace with him or not. The apostle knew that it would be difficult to get into and maintain such a state of peace, and this his own words amply prove: And if it be possible, as much as lieth in you, live peaceably. Though it be but barely possible, labor after it.

If it be possible, as much as lieth in you, live peaceably,.... Or be at peace, seek after peace, pursue it, and cultivate it:
with all men; with those that we are immediately concerned with, in a natural relation; so husbands should live peaceably with their wives, and wives with their husbands; parents with their children, and children with their parents; masters with their servants, and servants with their masters; and one brother, relation, and friend, with another: and so with all we are concerned with in a spiritual relation, as members of Christ, and in the same church state; such should be at peace among themselves, 1-Thessalonians 5:13; peace should rule in their hearts, Colossians 3:15, and they should study to keep "the unity of the Spirit, in the bond of peace", Ephesians 4:3, yea, with all we are concerned in a civil sense; saints should live peaceably in the neighbourhood, towns, cities, and countries, where they dwell, and show themselves to be the quiet in the land; should pray for the peace of the place where they are; and do all that in them lies to promote it, by living themselves peaceably and quietly, in all godliness and honesty; yea, they should live peaceably with their very enemies, "if it be possible"; which is rightly put, for there are some persons of such tempers and dispositions, that it is impossible to live peaceably with; for when others are for peace, they are for war; and in some cases it is not only impracticable, but would be unlawful; as when it cannot be done consistent with holiness of life and conversation, with the edification of others, the truths of the Gospel, the interest of religion, and the glory of God; these are things that are never to be sacrificed for the sake of peace with men: the apostle adds another limitation of this rule, "as much as lieth in you"; for more than this is not required of us; nothing should be wanting on our parts; every step should be taken to cultivate and maintain peace; the blame should lie wholly on the other side; it becomes the saints to live peaceably themselves, if others will not with them.

If it be possible--that is, If others will let you.
as much as lieth in you--or, "dependeth on you."
live peaceably--or, "be at peace."
with all men--The impossibility of this in some cases is hinted at, to keep up the hearts of those who, having done their best unsuccessfully to live in peace, might be tempted to think the failure was necessarily owing to themselves. But how emphatically expressed is the injunction to let nothing on our part prevent it! Would that Christians were guiltless in this respect!

Live peaceably with all men. If you can do so. Sometimes it is impossible. Sometimes sinners are exceedingly mad against the saints. But we are to be "peacemakers" (Matthew 5:9).
Beloved, avenge not yourselves. If we are injured, we are to leave the matter in the hands of God and give place unto his wrath. He sees and resents the injuries of his children.
For it is written. Deuteronomy 32:35. The Lord claims it as his prerogative to avenge what needs to be avenged. When we do it, we trample on the divine rights.
If thine enemy hunger, feed him. This is the spirit of Christ's command, to return good for evil. Compare Proverbs 25:21, Proverbs 25:23.
Thou shalt heap coals of fire on his head. Thou wilt by this kindness most readily subdue him, and make him feel most keenly the wrong he has done.
Be not overcome by evil. Don't let the fact that you are treated wickedly induce you to do wrong, but overcome evil by returning good for evil. This sums up the whole matter respecting the treatment of adversaries. Happy would it be if the Christian world could come up to these requirements! The logic of kind deeds is more powerful than the logic of argument.