John Calvin Commentary John 7:28

"Jesus therefore cried in the temple, teaching and saying, Ye both know me, and know whence I am; and I am not come of myself, but he that sent me is true, whom ye know not." — John 7:28 (ASV)

Jesus therefore exclaimed in the temple. He bitterly reproaches them for their rashness, because they arrogantly flattered themselves with a false opinion, and in this manner excluded themselves from the knowledge of the truth; as if he had said, “You know all things, and yet you know nothing.” And, indeed, there is not a more destructive plague than when men are so intoxicated by the scanty portion of knowledge which they possess, that they boldly reject everything that is contrary to their opinion.

You both know me, and you know from where I am. This is ironical language. With the false opinion they had formed concerning him, he contrasts what is true; as if he had said, “While you have your eyes fixed on the earth, you think that every part of me is before your eyes; and therefore you despise me as insignificant and unknown. But God will testify that I have come from heaven; and though I may be rejected by you, God will acknowledge that I am truly his own Son.”

But he who has sent me is true. He calls God true in the same sense that Paul calls him faithful.

If we are unbelievers, Paul says, he remaineth faithful, he cannot deny himself,
(2 Timothy 2:13).

For his object is to prove that the credit of the Gospel is not in the smallest degree diminished by the utmost exertions of the world to overthrow it; that though wicked men may attempt to take from Christ what belonged to him, still he remains unimpaired, because the truth of God is firm and is always like itself. Christ sees that he is despised; but so far is he from yielding, that, on the contrary, he boldly repels the furious arrogance of those who hold him in no esteem.

With such unshaken and heroic fortitude all believers should be endowed. Indeed, our faith will never be solid or lasting unless it treats with contempt the presumption of wicked men when they rise up against Christ. Above all, godly teachers, relying on this support, should persevere in maintaining sound doctrine, even though it should be opposed by the whole world. Thus Jeremiah appeals to God as his defender and guardian, because he is condemned as an impostor:

Thou hast deceived me, O Lord, he says, and I was deceived,
(Jeremiah 20:7).

Thus Isaiah, overwhelmed on all sides by slanders and reproaches, flies to this refuge: that God will approve his cause (Isaiah 50:8). Thus Paul, oppressed by unjust judgments, appeals against all to the day of the Lord (1 Corinthians 4:5), reckoning it enough to have God alone to set against the whole world, however it may rage and storm.

Whom you knew not. He means that it is not surprising that he is not known by the Jews, because they do not know God; for the beginning of wisdom is to behold God.