John Chrysostom
Catena Aurea · Johannesevangelium 6
Many therefore of his disciples, when they had heard this, said, This is an hard saying; who can hear it? When Jesus knew in himself that his disciples murmured at it, he said unto them, Doth this offend you? What and if ye shall see the Son of man ascend up where he was before? It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life. But there are some of you that believe not. For Jesus knew from the beginning who they were that believed not, and who should betray him. And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father. From that time many of his disciples went back, and walked no more with him. Then said Jesus unto the twelve, Will ye also go away? Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life. And we believe and are sure that thou art that Christ, the Son of the living God. Jesus answered them, Have not I chosen you twelve, and one of you is a devil? He spake of Judas Iscariot the son of Simon: for he it was that should betray him, being one of the twelve.
(Hom. xlvii. 2) The revelation however of these hidden things was a mark of His Divinity: hence the meaning of what follows; And if ye shall see the Son of man ascend up where He was before; supply, What will ye say? He said the same to Nathanael, Because I said to thee, I saw thee under the fig tree, believest thou? Thou shalt see greater things than these. He does not add difficulty to difficulty, but to convince them by the number and greatness of His doctrines. For if He had merely said that He came down from heaven, without adding any thing further, he would have offended His hearers more; but by saying that His flesh is the life of the world, and that as He was sent by the living Father, so He liveth by the Father; and at last by adding that He came down from heaven, He removed all doubt. Nor does He mean to scandalize His disciples, but rather to remove their scandal. For so long as they thought Him the Son of Joseph, they could not receive His doctrines; but if they once believed that He had come down from heaven, and would ascend thither, they would be much more willing and able to admit them.