John 6:61

58 This is the bread which came down out of heaven: not as the fathers ate, and died; he that eateth this bread shall live for ever.

59 These things said he in the synagogue, as he taught in Capernaum.

60 Many therefore of his disciples, when the heard [this], said, This is a hard saying; who can hear it?

61 But Jesus knowing in himself that his disciples murmured at this, said unto them, Doth this cause you to stumble?

62 [What] then if ye should behold the Son of man ascending where he was before?

63 It is the spirit that giveth life; the flesh profiteth nothing: the words that I have spoken unto you are spirit, are are life.

64 But there are some of you that believe not. For Jesus knew from the beginning who they were that believed not, and who it was that should betray him.