Then said Jesus unto them
Upbraiding them with their ignorance, and giving them a sign, as well as pointing out the time when they either, by good or sad experience, should have knowledge of him:
when ye have lift up the son of man;
meaning himself, who was to be lifted up upon the cross, as the serpent was upon the pole, in the wilderness; and which signified the manner of death he should die, the death of the cross; and suggested, that what the Jews designed for his reproach, shame, and abasement, would be the way and means of his rise and exaltation; and this lifting him up, or crucifying him, he ascribes to them, because they would deliver him to Pontius Pilate to be condemned, and stir up the people to ask, and be importunate themselves for his crucifixion:
then shall ye know that I am [he];
the Son of God, and true Messiah, as the centurion, and those that were with him, did, when they observed the earthquake; and the things that were done at his death; and after the death, resurrection, and ascension of Christ, and the pouring forth of his Spirit, many of the Jews had not only a notional, but a true and spiritual knowledge of Jesus, as the Messiah; and upon the destruction of their temple, city, and nation, and their disappointment by false Christs, they doubtless many of them must, and did know, that the true Messiah was come, and that Jesus of Nazareth was he:
and that I do nothing of myself; (See Gill on John 5:19);
but as my Father hath taught me, I speak these things;
this he says not as lessening himself, or making himself inferior to the Father, but to show the excellency of his doctrine, and to assert the original, authority, and divinity of it; suggesting that it was not an human doctrine, or a device of man's, or his own, as man, but was divine, and from God; see ( John 7:16 ) .