The Divine Institutes

And the nature of all these deceits is obscure to those who are without the truth. For they think that those demons profit them when they cease to injure, whereas they have no power except to injure. Some one may perchance say that they are therefore to be worshipped, that they may not injure, since they have the power to injure. They do indeed injure, but those only by whom they are feared, whom the powerful and lofty hand of God does not protect, who are uninitiated in the mystery of truth.

But they fear the righteous, that is, the worshippers of God, adjured by whose name they depart from the bodies of the possessed: for, being lashed by their words as though by scourges, they not only confess themselves to be demons, but even utter their own names— those which are adored in the temples— which they generally do in the presence of their own worshippers; not, it is plain, to the disgrace of religion, but to the disgrace of their own honour, because they cannot speak falsely to God, by whom they are adjured, nor to the righteous, by whose voice they are tortured.

Therefore ofttimes having uttered the greatest howlings, they cry out that they are beaten, and are on fire, and that they are just on the point of coming forth: so much power has the knowledge of God, and righteousness! Whom, therefore, can they injure, except those whom they have in their own power? In short, Hermes affirms that those who have known God are not only safe from the attacks of demons, but that they are not even bound by fate. “The only protection,” he says, “is piety, for over a pious man neither evil demon nor fate has any power: for God rescues the pious man from all evil; for the one and only good thing among men is piety.”

And what piety is, he testifies in another place, in these words: “For piety is the knowledge of God.” Asclepius also, his disciple, more fully expressed the same sentiment in that finished discourse which he wrote to the king. Each of them, in truth, affirms that the demons are the enemies and harassers of men, and on this account Trismegistus calls them wicked angels; so far was he from being ignorant that from heavenly beings they were corrupted, and began to be earthly.