Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XV

Chapter XV.—How Demons Get Power Over Men.

“Therefore demons, as we have just said, when once they have been able, by means of opportunities afforded them, to convey themselves through base and evil actions into the bodies of men, if they remain in them a long time through their own negligence, because they do not seek after what is profitable to their souls, they necessarily compel them for the future to fulfil the desires of the demons who dwell in them.  But what is worst of all, at the end of the world, when that demon shall be consigned to eternal fire, of necessity the soul also which obeyed him, shall with him be tortured in eternal fires, together with its body which it hath polluted.