Homilies on the First Epistle of John

^9. And what are those commandments? “This,” says he, “is His commandment, That we should believe in the name of His Son Jesus Christ, and love one another.” You see that this is the commandment: ye see that whoso does anything against this commandment, does the sin from which “every one that is born of God” is free. “As He gave us commandment:” that we love one another. “And he that keeps His commandment” — ye see that none other thing is bidden us than that we love one another— “And he that keeps His commandment shall abide in Him, and He in him.” And in this we know that He abides in us, by the Spirit which He has given us. Is it not manifest that this is what the Holy Ghost works in man, that there should be in him love and charity? Is it not manifest, as the Apostle Paul says, that “the love of God is shed abroad in our hearts by the Holy Ghost which is given us”? For [our apostle] was speaking of charity, and was saying that we ought in the sight of God to interrogate our own heart. “But if our heart think not ill of us:” i.e. if it confess that from the love of our brother is done in us whatever is done in any good work. And then besides, in speaking of the commandment, he says this: “This is His commandment, That we should believe in the name of His Son Jesus Christ, and love one another, as He gave us commandment.” “And he that does His commandment abides in Him, and He in him. In this we know that He abides in us, by the Spirit which He has given us.” If in truth you find that you have charity, you have the Spirit of God in order to understand: for a very necessary thing it is.