John the Apostle
John 5:33ESV·traditional attribution

You sent to John, and he has borne witness to the truth.

John Calvin Reformed @genevareformer

33. You sent to John. Before producing the testimony of God, he presses them with the answer of John, from which they could not honorably withhold their belief. For of what use was it to send to him, if they did not intend to abide by his words?

Matthew Henry Presbyterian @wholebiblehenry

In these verses our Lord Jesus proves and confirms the commission he had produced, and makes it out that he was sent of God to be the Messiah. I. He sets aside his own testimony of himself (Joh 5:31): "If I bear witness of myself, though it is infallibly true (Joh 8:14), yet, according to the common rule of judgment among men, you will not...

Commenting on John 5:31-47

John Gill Reformed Baptist @doctorgill

Ye sent unto John,.... The sanhedrim at Jerusalem made a deputation of priests and Levites to him, to know who he was, whether the Messiah, or Elias, or that prophet, Joh 1:19. Now had they not looked upon him, from what they knew of him, or from the character they had of him, as a faithful witness, they would never have shown him so much...