John 15:12 - Coke's Commentary on the Holy Bible

This is my commandment,— "As I told you before, ch. John 13:34.—the chief of all the commandments which I enjoin you, whether as apostles or private Christians, is, that ye love one another.—I do not mean after the hypocritical manner of the world, who often love in word, and in tongue, while nothing is more remote from their heart;—but in the sincere, tender, constant, manner of my love to you." Our Lord was thus earnest in pressing them to mutual love, not only because the great design of his gospel is to promote mutual love, but because this grace, exercised by the apostles among themselves, and towards all mankind, was one great means of making their preaching successful; just as the immense love of Christ to men will always have a great influence in drawing them to him. "They who are sensible of the great importance of this precept (says Dr. Heylin,) will not think the repetition of it here tautology."