Augustine of Hippo : "We are of God." Let us see why; see whether it be for any other thing than charity. "We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and of error:" namely by this, that he that heareth us hath the spirit of truth; he that heareth not us, hath the spirit of error. Let us see what he adviseth, and let us choose rather to hear him advising in the spirit of truth, and not antichrists, not lovers of the world, not the world. If we are born of God, "beloved," he goes on-see above from what: "We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and of error:" aye, now, he makes us eagerly attentive: to be told that he who knows God, hears; but he who knows not, hears not; and that this is the discerning between the spirit of truth and the spirit of error. — Ten Homilies on 1 John 7 Bede : We are of God. He who knows God, etc. For the carnal man does not receive the things of the Spirit of God, for they are foolishness to him. Therefore, he who does not want to hear the preachers of charity is undoubtedly known not to know God, nor to be of God, because he has neglected to imitate the charity that God has exercised towards men. — Commentary on the Catholic Epistles Bede : In this we know the Spirit of truth and the spirit of error. In this, indeed, because he who listens to us has the Spirit of truth; he who does not listen to us has the spirit of error. And this is the distinction of spirits, about which he warned above, saying: "Test the spirits to see whether they are of God." But let us see what he is about to admonish, in which we should hear him: — Commentary on the Catholic Epistles Didymus the Blind : If we take the word hear literally, it is clear that this cannot be true, since everybody can pick up the sounds of the words. It is therefore clear that the word means something more than that—it means that we should do what we hear. If someone does not know that he is supposed to act, he has not really heard. — COMMENTARY ON 1 JOHN Oecumenius : We are from God. Whoever knows God listens to us; whoever is not from God does not listen to us. By this we know the spirit of truth and the spirit of error. However, He listens to us who lives temperately, and whoever knows God, ready to give us hearing. Therefore, Christ also said: "He who has ears to hear, let him hear," (Matt. 11:15) testifying that only he who is prepared for obedience has ears. Having distinguished these, John then adds as a seal of those things already said, that through this (namely, what has already been said) we recognize those who have the spirit of truth or true prophetic dignity, and those who have the spirit of error or false prophecy. — Commentary on 1 John