John 6:59-64

59Jesus said these things in the synagogue, as he taught at Capernaum.

60When many of his disciples heard it, they said, "This is a hard saying; who can listen to it?"

61But Jesus, knowing in himself that his disciples were grumbling about this, said to them, "Do you take offense at this?

62Then what if you were to see the Son of Man ascending to where he was before?

63It is the Spirit who gives life; the flesh is no help at all. The words that I have spoken to you are spirit and life.

64But there are some of you who do not believe." (For Jesus knew from the beginning who those were who did not believe, and who it was who would betray him.)