appetite; as
is the case with one who is possessed. But then, the reason being
thus fettered, whatever man may do, it is not imputed to him as a
sin. If, however, the reason is not altogether fettered, then, in so
far as it is free, it can resist sin, as stated above (Q. 77, A. 7).
It is consequently evident that the devil can nowise compel man to
sin.

Reply Obj. 1: Not every power that is greater than man, can move
man's will; God alone can do this, as stated above (Q. 9, A. 6).

Reply Obj. 2: That which is apprehended by the senses or the
imagination does not move the will, of necessity, so long as man has
the use of reason; nor does such an apprehension always fetter the
reason.

Reply Obj. 3: The lusting of the flesh against the spirit, when the
reason actually resists it, is not a sin, but is matter for the
exercise of virtue. That reason does not resist, is not in the
devil's power; wherefore he cannot bring about the necessity of
sinning.
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FOURTH ARTICLE [I-II, Q. 80, Art. 4]

Whether All the Sins of Men Are Due to the Devil's Suggestion?

Objection 1: It would seem that all the sins of men are due to the
devil's suggestion. For Dionysius says (Div. Nom. iv) that the "crowd
of demons are the cause of all evils, both to themselves and to
others."

Obj. 2: Further, whoever sins mortally, becomes the slave of the
devil, according to John 8:34: "Whosoever committeth sin is the slave
[Douay: 'servant'] of sin." Now "by whom a man is overcome, of the
same also he is the slave" (2 Pet. 2:19). Therefore whoever commits a
sin, has been overcome by the devil.

Obj. 3: Further, Gregory says (Moral. iv, 10) the sin of the devil is
irreparable, because he sinned at no other's suggestion. Therefore,
if any men were to sin of their own free-will and without suggestion
from any other, their sin would be irremediable: which is clearly
false. Therefore all the sins of men are due to the devil's
suggestion.

_On the contrary,_ It is written (De Eccl. Dogm. lxxxii): "Not all
our evil thoughts are incited by the devil; sometimes they are due to
a movement of the free-will."

_I answer that,_ the devil is the occasional and indirect cause of
all our sins, in so far as he induced the first man to sin, by reason
of whose sin human nature is so infected, that we are all prone to
sin: even as the burning of wood might be imputed to the man who
dried the wood so as to make it easily inflammable. He