John 6:63-66

King James Version

⁶³ It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they 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 should betray him.

⁶⁵ And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father.

⁶⁶ From that time many of his disciples went back, and walked no more with him.