John 13:34-35

Verse 34. A new commandment. This command he gave them as he was about to leave them, to be a badge of discipleship, by which they might be known as his friends and followers, and by which they might be distinguished from all others. It is called new, not because there was no command before which required men to love their fellow-men, for one great precept of the law was that they should love their neighbour as themselves (Lev 19:18); but it was new because it had never before been made that by which any class or body of men had been known and distinguished. The Jew was known by his external rites, by his peculiarity of dress, &c.; the philosopher by some other mark of distinction; the military man by another, &c. In none of these cases had love for each other been the distinguishing and peculiar badge by which they were known. But in the case of Christians they were not to be known by distinctions of wealth, or learning, or fame; they were not to aspire to earthly honours; they were not to adopt any peculiar style of dress or badge, but they were to be distinguished by tender and constant attachment to each other. This was to surmount all distinction of country, of colour, of rank, of office, of sect. Here they were to feel that they were on a level, that they had common wants, were redeemed by the same sacred blood, and were going to the same heaven. They were to befriend each other in trials; be careful of each other's feelings and reputation; deny themselves to promote each other's welfare. See 1Jn 3:23, 1Thes 4:9, 1Pet 1:22, 2Thes 1:3; Gal 6:2, 2Pet 1:7. In all these places the command of Jesus is repeated or referred to, and it shows that the first disciples considered this indeed as the peculiar law of Christ. This command or law was, moreover, new in regard to the extent to which this love was to be carried; for he immediately adds, "As I have loved you, that ye also love one another." His love for them was strong, continued, unremitting, and he was now about to show his love for them in death. Jn 15:13, "Greater love hath no man than this, that a man lay down his life for his friends." So in 1Jn 3:16 it is said that "we ought also to lay down our lives for the brethren." This was a new expression of love; and it showed the strength of attachment which we ought to have for Christians, and how ready we should be to endure hardships, to encounter dangers, and to practise self-denial, to benefit those for whom the Son of God laid down his life.

(x) "new commandment" Lev 19:18, Jn 15:12,17, Eph 5:2, 1Thes 4:9 Jas 2:8, 1Pet 1:22, 1Jn 2:7,8, 3:11,23, 4:20,21
Verse 35. By this shall all men, &c. That is, your love for each other shall be so decisive evidence that you are like the Saviour, that all men shall see and know it. It shall be the thing by which you shall be known among all men. You shall not be known by peculiar rites or habits; not by a peculiar form of dress or manner of speech; not by peculiar austerities and unusual customs, like the Pharisees, the Essenes, or the scribes, but by deep, genuine, and tender affection. And it is well known it was this which eminently distinguished the first Christians, and was the subject of remark by the surrounding pagans. "See," said the heathen, "see how they love one another! They are ready to lay down their lives for each other." Alas! how changed is the spirit of the Christian world since then! Perhaps, of all the commands of Jesus, the observance of this is that which is least apparent to a surrounding world. It is not so much that they are divided into different sects, for this may be consistent with love for each other; but it is the want of deep-felt, genuine love toward Christians even of our own denomination; the absence of genuine self-denial; the pride of rank and wealth; and the fact that professed Christians are often known by anything else rather than by true attachment to those who bear the same Christian name and image. The true Christian loves religion wherever it is found--equally in a prince or in a slave, in the mansion of wealth or in the cottage of poverty, on the throne or in the hut of want. He overlooks the distinction of sect, of colour, and of nations; and wherever he finds a man who bears the Christian name and manifests the Christian spirit, he loves him. And this, more and more as the millennium draws near, will be the peculiar badge of the professed children of God. Christians will love their own denominations less than they love the spirit and temper of the Christian, wherever it may be found.
Copyright information for Barnes