John 8:30

When our Lord said, He is true that sent Me, the Jews did not understand that He spoke to them of the Father. But He saw some there, who, He knew, would believe on Him after His passion. Then said Jesus to them, When you have lifted up the Son of man, then you shall know that I am. Recollect the words, I am that I am, and you will know why I say, I am. I pass over your knowledge, in order that I may fulfill My passion. In your appointed time you will know who I am; when you have lifted up the Son of man. He means the lifting up of the cross; for He was lifted up on the cross, when He hung thereon. This was to be accomplished by the hands of those who should afterwards believe, whom He is now speaking to; with what intent, but that no one, however great his wickedness and consciousness of guilt might despair, seeing even the murderers of our Lord forgiven.

Or the connection is this: When His miracles and teaching had failed to convert men, He spoke of the cross; When you have lifted up the Son of man, then you shall know that I am He: as if to say, you think that you have killed Me; but I say that you shall then, by the evidence of miracles, of My resurrection, and your captivity, know most especially, that I am Christ the Son of God, and that I do not act in opposition to God; But that as My Father has taught Me, I speak these things. Here He shows the likeness of His substance to the Father’s; and that He says nothing beyond the Paternal intelligence. If I were contrary to God, I should not have moved His anger so much against those who did not hear Me.

Or thus: Having said, Then shall you know that I am, and in this, I am, implied the whole Trinity: lest the Sabellian error should creep in, He immediately adds, And I do nothing of Myself; as if to say, I am not of Myself; the Son is God from the Father. Let not what follows, as the Father has taught Me, I speak these things, suggest a carnal thought to any of you. Do not place as it were two men before your eyes, a Father speaking to his son, as you do when you speak to your sons. For what words could be spoken to the only Word? If the Father speaks in your hearts without sound, how does he speak to the Son? The Father speaks to the Son incorporeally, because He begat the Son incorporeally: not did He teach Him, as having begotten Him untaught; rather the teaching Him, was the begetting Him knowing. For if the nature of truth be simple, to be, in the Son, is the same as to know. As then the Father gave the Son existence by begetting, so He gave Him knowledge also.

He gives now a humbler turn to the discourse: And He that sent Me. That this might not be thought however to imply inferiority, He says, Is with Me. The former is His dispensation, the latter His divinity.

And though both are together, yet one is sent, the other sends. For the mission is the incarnation; and the incarnation is of the Son only, not of the Father. He says then, He that sent Me, meaning, By whose Fatherly authority I am made incarnate. The Father however, though He sent the Son, did not withdraw from Him, as He proceeds to say: The Father has not left Me alone. For it could not be that where He sent the Son, there the Father was not, He who says, If in heaven and earth. And He adds the reason why He did not leave Him: For I do always those things that please Him; always, i.e. not from any particular beginning, but without beginning and without end. For the generation from the Father has no beginning in time.

Or, He means it as an answer to those who were constantly saying that He was not from God, and that because He did not keep the sabbath; I do always, He says, do those things that please Him; showing that the breaking the sabbath even was pleasing to Him. He takes care in every way to show that He does nothing contrary to the Father. And as this was speaking more after a human fashion, the Evangelist adds, As He spoke these words many believed in Him; as if to say, Do not be disturbed at hearing so humble a speech from Christ; for those who had heard the greatest doctrines from Him, and were not persuaded, were persuaded by these words of humility. These then believed on Him, yet not as they ought; but only out of joy, and approbation of His humble way of speaking. And this the Evangelist shows in his subsequent narration, which relates their unjust proceedings towards Him.

2. In this prayer, therefore, Jesus may seem to have omitted praying for some of His own, unless we carefully examine His words in the prayer itself. For if He prayed first for those, as we have already shown, who were then with Him, and afterwards for those also who should believe on Him through their word, it may be said that He prayed not for those who were neither with Him when He so spake, nor afterwards believed through their word, but had done so at some previous time either of themselves, or in some other supposable manner. …

Ver. 30 . “As He spake these words, many believed on Him.” When He brought down His speech to a lowly strain, many believed on Him. Dost thou still ask wherefore He speaketh humbly? Yet the Evangelist clearly alluded to this when he said, “As He spake these things, many believed on Him.” By this all but proclaiming aloud to us, “Oh hearer, be not confounded if thou hear any lowly expression, for they who after such high teaching were not yet persuaded that He was of the Father, were with good reason made to hear humbler words, that they might believe.” And this is an excuse for those things which shall be spoken in a humble way. They believed then, yet not as they ought, but carelessly and as it were by chance, being pleased and refreshed by the humility of the words. For that they had not perfect faith the Evangelist shows by their speeches after this, in which they insult Him again. …