Nicene and Post-Nicene Fathers, Vol. II:
City of God: Chapter 6

Chapter 6.—Of the Passions Which, According to Apuleius, Agitate the Demons Who Are Supposed by Him to Mediate Between Gods and Men.

Deferring for the present the question about the holy angels, let us examine the opinion of the Platonists, that the demons who mediate between gods and men are agitated by passions.  For if their mind, though exposed to their incursion, still remained free and superior to them, Apuleius could not have said that their hearts are tossed with passions as the sea by stormy winds. 344   Their mind, then,—that superior part of their soul whereby they are rational beings, and which, if it actually exists in them, should rule and bridle the turbulent passions of the inferior parts of the soul,—this mind of theirs, I say, is, according to the Platonist referred to, tossed with a hurricane of passions.  The mind of the demons, therefore, is subject to the emotions of fear, anger, lust, and all similar affections.  What part of them, then, is free, and endued with wisdom, so that they are pleasing to the gods, and the fit guides of men into purity of life, since their very highest part, being the slave of passion and subject to vice, only makes them more intent on deceiving and seducing, in proportion to the mental force and energy of desire they possess?

Footnotes

De Deo Soc.