66 After this many of his disciples turned back and no longer walked with him. 67 So Jesus said to the Twelve, “Do you want to go away as well?”
68 Simon Peter answered him, “Lord, to whom shall we go? You have the words of eternal life, 69 and we have believed, and have come to know, that you are the Holy One of God.” 70 Jesus answered them, “Did I not choose you, the Twelve? And yet one of you is a devil.” 71 He spoke of Judas the son of Simon Iscariot, for he, one of the Twelve, was going to betray him.
John 6:66-71 (ESV)