John 14:30
“Hereafter I will not talk with you.” Wherefore? “For the ruler of this world comes, and has nothing in Me.”
By “ruler of this world,” He means the devil, calling wicked men also by the same name. For he rules not heaven and earth, since he would have been subverted, and cast down all things, but he rules over those who give themselves up to him. Wherefore He calls him, “the ruler of the darkness of this world,” in this place again calling evil deeds, “darkness.” “What then, does the devil slay You?” By no means; “he has nothing in Me.” “How then do they kill You?” Because I will it, and,
Source: Homilies on the Gospel of John (New Advent)