Since, on the other hand, you are oppressed by strange sufferings inflicted by demons, on your removal from the body you shall have your souls also punished for ever; not indeed by God’s inflicting vengeance, but because such is the judgment of evil deeds. For the demons, having power by means of the food given to them, are admitted into your bodies by your own hands; and lying hid there for a long time, they become blended with your souls.
And through the carelessness of those who think not, or even wish not, to help themselves, upon the dissolution of their bodies, their souls being united to the demon, are of necessity borne by it into whatever places it pleases. And what is most terrible of all, when at the end of all things the demon is first consigned to the purifying fire, the soul which is mixed with it is under the necessity of being horribly punished, and the demon of being pleased. For the soul, being made of light, and not capable of bearing the heterogeneous flame of fire, is tortured; but the demon, being in the substance of his own kind, is greatly pleased, becoming the strong chain of the soul that he has swallowed up.
Chapter X. How They are to Be Expelled
But the reason why the demons delight in entering into men’s bodies is this. Being spirits, and having desires after meats and drinks, and sexual pleasures, but not being able to partake of these by reason of their being spirits, and wanting organs fitted for their enjoyment, they enter into the bodies of men, in order that, getting organs to minister to them, they may obtain the things that they wish, whether it be meat, by means of men’s teeth, or sexual pleasure, by means of men’s members.
Hence, in order to the putting of demons to flight, the most useful help is abstinence, and fasting, and suffering of affliction. For if they enter into men’s bodies for the sake of sharing pleasures, it is manifest that they are put to flight by suffering. But inasmuch as some, being of a more malignant kind, remain by the body that is undergoing punishment, though they are punished with it, therefore it is needful to have recourse to God by prayers and petitions, refraining from every occasion of impurity, that the hand of God may touch him for his cure, as being pure and faithful.