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 theylove 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, Le 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 Ro 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 , 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 another; than which, nothing can, or should, more strongly engage to it: as Christ has loved his people freely, notwithstanding all their unworthiness and ungratefulness, so should they love one another, though there may be many things in them observable, which are disagreeable; as Christ loves all his children without any distinction, so should they love one another, whether poor or rich, weaker or stronger, lesser or greater believers; and as Christ loves them not in word only, but in deed and in truth, so should they love one another with a pure heart fervently, and by love serve one another.
R. Isaac Chizzuk Emuna, l. 2. c. 54. p.