Against Celsus 1.6

After this, moved by I know not what, Celsus says that Christians seem to get their power from the names of certain demons and from incantations, hinting, I suppose, at those who charm and drive out demons. But he seems plainly to be slandering the teaching. For they do not seem to get their power from incantations but from the name of Jesus, together with the recital of the stories about him. For these, when spoken, have often made demons leave human beings, especially when those who speak them speak from a sound disposition and genuine faith. Indeed the name of Jesus has such power against the demons that sometimes it is effective even when named by wicked men. Jesus taught this when he said: "Many will say to me on that day: In your name we cast out demons and did mighty works." I do not know whether Celsus passed this over deliberately and maliciously or through ignorance. In what follows he accuses the Savior too, as having been able by sorcery to do the seemingly wonderful things he did, and as foreseeing that others, having learned the same lessons, would do the same, boasting that they do it by the power of God—people whom Jesus drives out of his own commonwealth. And he accuses him thus: if he rightly drives them out while guilty of the same things himself, he is wicked; but if he is not wicked for doing these things, neither are those who act as he did. On the contrary, even if it seems impossible to prove how Jesus did these things, it is clear that Christians use no practice of incantations but succeed by the name of Jesus and other words believed according to divine Scripture.