John 8:12–20

Verse 14. Although I give testimony (or witness) of myself, my testimony is true. He gives them the reason, verse 16; because he is not alone, but the Father (who also beareth witness) is also with him. Witham.

Verse 15. You judge, and also bear testimony concerning other men, according to the flesh, and according to outward shew and appearances only. I judge no one in this manner. And whatever judgment I pass, or if I give testimony, my testimony is true, as coming also from the Father, with whom I am one in nature, though a distinct person: and two, according to the law, are enough to give evidence. Witham.—You judge according to the flesh, and so forth Because you do not understand the ways of God, and think you only see in me the person of man; therefore I seem to you to be arrogant, bearing witness of myself. Man indeed, who wishes alone to bear testimony of himself, is arrogant, and not to be believed, because all men are frail and liable to be deceived; but light and truth itself can neither deceive nor be deceived. Saint Augustine

Verse 16. I am not alone. Christ does not here say that he is the Father and he is the Son, he only says that he is not alone, but that the Father is with him, plainly distinguishing the two Persons. The Father is truly the Father, and the Son truly the Son, not one elder or greater than the other, but both entirely equal in all perfections. One in substance, co-eternal, and of one perfect equality. Saint Augustine

Verse 19. Where is thy Father? They knew well enough by other discourses, that he had called and declared God to be his Father; but they had a mind to make him own it again, that they might accuse him as guilty of blasphemy.—Neither me do you know, nor my Father: you will not own me to have been always his Son, nor him to have been always my Father, but did you know me to be his Son, always proceeding from him, you would know my Father also, and know him as my Father from all eternity. Witham.—As in common conversation we often say, “when you have seen one, you have seen the other;” when two persons or things seem perfectly alike as to outward appearances, so here Christ says, If you did know me, you would know my Father also: not that the Father is the Son, or the Son the Father, but because the Father is like the Son. Saint Augustine—Here might the Arians, and all who maintain that Christ is a mere creature, blush; for if he were a creature, how can any one who knows him likewise know God? Therefore is Christ consubstantial with the Father, for he who knows the Son, knows the Father also. Theophyl.