Augustine of Hippo : He had said, "Let us not love only in word and in tongue, but in work and in truth:" we are asked, In what work, or in what truth, is he known that loveth God, or loveth his brother? Above he had said up to what point charity is perfected: what the Lord saith in the Gospel, "Greater love than this hath no man, that one lay down his life for his friends," this same had the apostle also said: "As He laid down His life for us, we ought also to lay down our lives for the brethren." This is the perfection of charity, and greater can not at all be found. But because it is not perfect in all, and that man ought not to despair in whom it is not perfect, if that be already born which may be perfected: and of course if born, it must be nourished, and by certain nourishments of its own must be brought unto its proper perfection. — Ten Homilies on 1 John 6 Augustine of Hippo : This it is then that he enforces here. "In this we know that we are of the truth, when in deed and in truth" we love, "not only in words and in tongue: and assure our heart before Him." What meaneth, "before Him?" Where He seeth. Whence the Lord Himself in the Gospel saith: "Take heed that ye do not your righteousness before men, to be seen of them: otherwise ye have no reward with your Father which is in heaven." And what meaneth, "Let not thy left hand know what thy right hand doeth:" except that the right hand means a pure conscience, the left hand the lust of the world? Many through lust of the world do many wonderful things: the left hand worketh, not the right. The right hand ought to work, and without knowledge of the left hand, so that lust of the world may not even mix itself therewith when by love we work aught that is good. And where do we get to know this? Thou art before God: question thine heart, see what thou hast done, and what therein was thine aim; thy salvation, or the windy praise of men. — Ten Homilies on 1 John 6 Bede : In this we know that we are of the truth. That is, when we perform acts of piety in truth, it is evident that we are of the truth, which is God, just as we imitate His perfection according to our capacity. — Commentary on the Catholic Epistles Bede : And shall assure our hearts before Him. This statement depends on what preceded. Because when we love our neighbors in deed and truth, we clearly know that we assure our hearts in the sight of the supreme truth. For all men, when they intend to do something, persuade their hearts to meditate on that thing to be done. But those who think evil would, if they could, hide these things from God; as He testifies who says: For everyone who does evil hates the light and does not come to the light, lest his deeds should be exposed (John 3); but those who meditate on doing good easily persuade their hearts to desire to be revealed before the divinity, which is a sign of the highest perfection when each one rejoices that his deeds or thoughts are seen by God. Hence, He subsequently says: But he who does the truth comes to the light, that his deeds may be clearly seen, that they have been done in God (Ibid.). Through true love, therefore, we know that we are of the truth, and that we assure our hearts before the same truth, that is, we persuade our hearts to have such thoughts as are worthy of divine sight. — Commentary on the Catholic Epistles Oecumenius : By this we know that we are of the truth, and before Him we shall assure our hearts. For if our heart condemns us, God is greater than our heart, and knows all things. "By this we know." By what? From the fact that we do not love in word, but in action and in truth. And what do we know? That we are of the truth. How? For he who says one thing and does another, not having an action conforming to his speech, is a liar and not truthful. "and before Him we shall assure our hearts." That is to say, what John means is that by this, namely that we are truthful (furthermore, we will be truthful when our actions continue according to our words), we will assure our conscience, for he wishes to signify this by "hearts". And how shall we assure? By placing this among ourselves, as we express our words with God as our witness. For this means in His sight, or before Him. Indeed, if we do not do so, John says, but our conscience or heart condemns us, it does not hide that we are sinning. If our conscience, which is small as it comes from a small creature, cannot be hidden while we sin, much more can God, who is limitless and everywhere, not be hidden. Therefore, the whole discourse is this: My little children, let us not lie to one another, loving only in word, but let us also show our love through actions: for by this we will be known that we are of the truth, that is, from God; and let us speak as if God were watching. Indeed, no one, even if he were more shameless than demons, could bear to lie in the presence and sight of God. For if we do not act so, but by saying that we love, our heart will accuse us of falsehood; we err. How? By thinking that God is hidden, who is present everywhere? And not knowing that if it cannot be that our heart, when it is small, is hidden, much less will He be hidden who is never absent. — Commentary on 1 John Shepherd of Hermas : On hearing these words, I wept most violently. When he saw me weeping, he said to me, "Why do you weep?" And I said, "Because, sir, I know not if I can be saved." "Why?" said he. And I said, "Because, sir, I never spake a true word in my life, but have ever spoken cunningly to all, and have affirmed a lie for the truth to all; and no one ever contradicted me, but credit was given to my word. How then can I live, since I have acted thus?" And he said to me, "Your feelings are indeed right and sound, for you ought as a servant of God to have walked in truth, and not to have joined an evil conscience with the spirit of truth, nor to have caused sadness to the holy and true Spirit." And I said to him, "Never, sir, did I listen to these words with so much attention." And he said to me, "Now you hear them, and keep them, that even the falsehoods which you formerly told in your transactions may come to be believed through the truthfulness of your present statements. For even they can become worthy of credit. If you keep these precepts, and from this time forward you speak nothing but the truth, it will be possible for you to obtain life." — Shepherd of Hermas, Commandment 3