Tractates on the Gospel of John

² It was after this bread, then, that Satan entered into the Lord's betrayer, that, as now given over to his power, he might take full possession of one into whom before this he had only entered in order to lead him into error. For we are not to suppose that he was not in him when he went to the Jews and bargained about the price of betraying the Lord; for the evangelist Luke very plainly attests this when he says: “Then entered Satan into Judas, who was surnamed Iscariot, being one of the twelve; and he went his way, and communed with the chief priests.” Here, you see, it is shown that Satan had already entered into Judas. His first entrance, therefore, was when he implanted in his heart the thought of betraying Christ; for in such a spirit had he already come to the supper. But now, after the bread, he entered into him, no longer to tempt one who belonged to another, but to take possession of him as his own.