34.A new commandment I give you. To the consolation he adds an exhortation,that they should love one another; as if he had said, “ while I am absent from you in body, testify, by mutual love, that I have not taught you in vain; let this be your constant study, your chief meditation.” Why does he call it a new commandment ? All are not agreed on this point. There are some who suppose the reason to be, that, while the injunction formerly contained in the Law about brotherly love was literal and external, Christ wrote it anew by his Spirit on the hearts of believers. Thus, according to them, the Law is new, because he publishes it in a new manner, that it may have full vigor. But that is, in my opinion, far-fetched, and at variance with Christ’ meaning. The exposition given by others is, that, though the Law directs us to the exercise of love, still, because in it the doctrine of brotherly love is encumbered by many ceremonies and appendages, it is not so clearly exhibited; but, on the other hand, that perfection in love is laid down in the Gospel without any shadows. For my own part, though I do not absolutely reject this interpretation, I consider what Christ said to be more simple; for we know that laws are more carefully observed at the commencement, but they gradually slip out of the remembrance of men, till at length they become obsolete. In order to impress more deeply, therefore, on the minds of his disciples the doctrine of brotherly love, Christ recommends it on the ground of novelty; as if he had said, “ wish you continually to remember this commandment, as if it had been a law but lately made.”
In short, we see that it was the design of Christ, in this passage, to exhort his disciples to brotherly love, that they might never permit themselves to be withdrawn from the pursuit of it, or the doctrine of it to slip out of their minds. And how necessary this admonition was, we learn by daily experience; for, since it is difficult to maintain brotherly love, men lay it aside, and contrive, for themselves, new methods of worshipping God, and Satan suggests many things for the purpose of occupying their attention. Thus, by idle employments, they in vain attempt to mock God, but they deceive themselves. Let this title of novelty, therefore, excite us to the continual exercise of brotherly love. Meanwhile, let us know that it is called new, not because it now began, for the first time, to please God, since it is elsewhere called the fulfilling of the law, (Rom_13:10.)
That you love one another. Brotherly love is, indeed, extended to strangers, for we are all of the same flesh, and are all created after the image of God; but because the image of God shines more brightly in those who have been regenerated, it is proper that the bond of love, among the disciples of Christ, should be far more close. In God brotherly love seeks its cause, from him it has its root, and to him it is directed. Thus, in proportion as it perceives any man to be a child of God, it embraces him with the greater warmth and affection. Besides, the mutual exercise of love cannot exist but in those who are guided by the same Spirit. It is the highest degree of brotherly love, therefore, that is here described by Christ; but we ought to believe, on the other hand, that, as the goodness of God extends to the whole world, so we ought to love all, even those who hate us.
As I have loved you. He holds out his own example, not because we can reach it, for we are at a vast distance behind him, but that we may, at least, aim at the same end.