"Now that the demons are desirous of occupying the bodies of men, this is the reason. They are spirits having their purpose turned to wickedness. Therefore by immoderate eating and drinking, and lust, they urge men on to sin; but only those who entertain the purpose of sinning, who, while they seem simply desirous of satisfying the necessary cravings of nature, give opportunity to the demons to enter into them, because through excess they do not maintain moderation. For as long as the measure of nature is kept, and legitimate moderation is preserved, the mercy of God does not give them liberty to enter into men. But when either the mind falls into impiety, or the body is filled with immoderate meat or drink, then, as if invited by the will and purpose of those who thus neglect themselves, they receive power as against those who have broken the law imposed by God.