John 6:62-64

⁶²What if ye shall see the Son of man ascend up where he was before?

⁶³It is the spirit that reviveth; the flesh profiteth nothing: the words that I speak to you, they are spirit, and they are life.

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