John 6:62

[What] and if ye shall see the son of man
Meaning himself then in a state of humiliation, and was taken for a mere man, though the true Messiah, and Son of God:

ascend up where he was before?
for Christ was, he existed before his incarnation, and he was in heaven before; not in his human nature, but as the word and Son of God: and he intimates, that when he had done his work, and the will of his Father, for which he came down from heaven, by the assumption of the human nature, he should ascend up thither again; and which would be seen, as it was, by his apostles; and which would prove that he came down from heaven, as he had asserted; see ( Ephesians 4:9 Ephesians 4:10 ) ; and that his flesh and blood were not to be eaten in a corporeal sense; in which sense they understood him: and he hereby suggests, that if it was difficult to receive, and hard to be understood, and was surprising and incredible, that he should come down from heaven, as bread, to be eat and fed upon; it would be much more so to them to be told, that he who was in so mean and lowly a form, should ascend up into heaven.