John 6:61-64

61Aware that his disciples were grumbling about this, Jesus said to them, “Does this offend you? 62Then what if you see the Son of Man ascend to where he was before! 63The Spirit gives life; the flesh counts for nothing. The words I have spoken to you—they are full of the Spirit Or are Spirit; or are spirit and life. 64Yet there are some of you who do not believe.” For Jesus had known from the beginning which of them did not believe and who would betray him.