John 13:34

A new commandment I give unto you - In what sense are we to understand that this was a new commandment? Thou shalt love thy neighbor as thyself, was a positive precept of the law, Lev 19:18, and it is the very same that Christ repeats here; how then was it new? Our Lord answers this question, Even As I have loved you. Now Christ more than fulfilled the Mosaic precept; he not only loved his neighbor As himself, but he loved him More than himself, for he laid down his life for men. In this he calls upon the disciples to imitate him; to be ready on all occasions to lay down their lives for each other. This was, strictly, a new commandment: no system of morality ever prescribed any thing so pure and disinterested as this. Our blessed Lord has outdone all the moral systems in the universe in two words: 1. Love your enemies; 2. Lay down your lives for each other.

a new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another--This was the new feature of it. Christ's love to His people in giving His life a ransom for them was altogether new, and consequently as a Model and Standard for theirs to one another. It is not, however, something transcending the great moral law, which is "the old commandment" (Jo1 2:7, and see on Mar 12:28-33), but that law in a new and peculiar form. Hence it is said to be both new and old (Jo1 2:7-8).

A new commandment I give unto you,.... As parents, when they take their leave of their children, in their dying moments, give them proper instructions and orders, and lay their dying injunctions on them, so Christ taking his leave of his disciples, gives them his; which were, that they love one another: as brethren in the same family, children of the same Father, and fellow disciples with each other; by keeping and agreeing together, praying one for another, bearing one another's burdens, forbearing and forgiving one another, admonishing each other, and building up one another in faith and holiness: and this he calls "a new commandment"; that is, a very excellent one; as a "new name", and a "new song", denote excellent ones; or it is so called, because it is set forth by Christ, in a new edition of it, and newly and more clearly explained, than before; and being enforced with a new argument and pattern, never used before, as I have loved you; and to be observed in a new manner, not "in the oldness of the letter, but in the newness of the spirit": besides, though this commandment, as to the matter of it, is the same with that of Moses, Lev 19:18; yet it takes in more, and "new" objects; since by "neighbour" there, seems to be meant "the children of their people", the Jews; and so they understood it only of their countrymen, and of proselytes at furthest, whereas this reaches to any "other" person; see Rom 13:8; and as the measure, as well as the motive is new, for it is not now "as thy self", but "as I have loved you", the Jew has no reason to object as he does (m), to its being called a "new commandment": and its being "new", carries in it a reason or argument, why it should be observed, as does also the following clause; as I have loved you, that ye also love one anoth…

Our Saviour having finished his public discourses, in which he "endured the contradiction of sinners," now applies himself to a private conversation with his friends, in which he designed the consolation of saints. Henceforward we have an account of what passed between him and his disciples, who were to be entrusted with the affairs of his household, when he was gone into a far country; the necessary instructions and comforts he furnished them with. His hour being at hand, he applies himself to set his house in order. In this chapter I. He washes his disciples' feet (v. 1-17). II. He foretels who should betray him (Joh 13:18-30). III. He instructs them in the great doctrine of his own death, and the great duty of brotherly love (Joh 13:31-35). IV. He foretels Peter's denying him (Joh 13:36-38).

13:34-35 That the disciples were to love one another was not a new commandment (see Lev 19:18). However, that they were to love each other with the sort of love modeled by Jesus was dramatic. Jesus’ love for God was expressed in perfect obedience (John 14:31); now this kind of love was his command—that disciples express their love for Jesus in committed obedience.