John Calvin on John 6:58

58. This is the bread which came down from heaven. He returns to the comparison between the manna and his flesh, with which he had begun; for it was necessary that he should close the sermon in this manner: “There is no reason why you should prefer Moses to me, because he fed your fathers in the wilderness; since I supply you with far more excellent food, for I bring heavenly life with me.” For — as was formerly said — the bread is said to have come down from heaven, because it has nothing earthly or corruptible in its nature, but breathes the immortality of the kingdom of God. They who were only bent on feeding the belly, did not find such virtue in the manna; for while the manna had a twofold use, the Jews, with whom Christ is now disputing, beheld in it nothing else than bodily food. But the life of the soul is not fading, but makes continual progress until the whole man is renewed.

John 6:59-64

59 He spoke these things in the synagogue, while he was teaching in Capernaum. 60. Many of his disciples, therefore, having heard it, said, This is a harsh saying; “Ceste parole est dure, ou, rude;” — “this saying hard, or, harsh.” who can hear it? 61. But Jesus knowing in himself that his disciples murmured at it, said to them, Doth this offend you? 62. What if you shall see the Son of man ascend to where he was before? 63. It is the Spirit that quickeneth; the flesh profiteth nothing. The words which I speak to you are spirit and life. 64. But there are some of you who do not believe. For Jesus knew from the beginning who they were that did not believe, and who he was that would betray him.