Q. 20, Art. 1]

Whether Despair Is a Sin?

Objection 1: It would seem that despair is not a sin. For every sin
includes conversion to a mutable good, together with aversion from
the immutable good, as Augustine states (De Lib. Arb. ii, 19). But
despair includes no conversion to a mutable good. Therefore it is not
a sin.

Obj. 2: Further, that which grows from a good root, seems to be no
sin, because "a good tree cannot bring forth evil fruit" (Matt.
7:18). Now despair seems to grow from a good root, viz. fear of God,
or from horror at the greatness of one's own sins. Therefore despair
is not a sin.

Obj. 3: Further, if despair were a sin, it would be a sin also for
the damned to despair. But this is not imputed to them as their fault
but as part of their damnation. Therefore neither is it imputed to
wayfarers as their fault, so that it is not a sin.

_On the contrary,_ That which leads men to sin, seems not only to be
a sin itself, but a source of sins. Now such is despair, for the
Apostle says of certain men (Eph. 4:19): "Who, despairing, have given
themselves up to lasciviousness, unto the working of all uncleanness
and [Vulg.: 'unto'] covetousness." Therefore despair is not only a
sin but also the origin of other sins.

_I answer that,_ According to the Philosopher (Ethic. vi, 2)
affirmation and negation in the intellect correspond to search and
avoidance in the appetite; while truth and falsehood in the intellect
correspond to good and evil in the appetite. Consequently every
appetitive movement which is conformed to a true intellect, is good
in itself, while every appetitive movement which is conformed to a
false intellect is evil in itself and sinful. Now the true opinion of
the intellect about God is that from Him comes salvation to mankind,
and pardon to sinners, according to Ezech. 18:23, "I desire not the
death of the sinner, but that he should be converted, and live"
[*Vulg.: 'Is it My will that a sinner should die . . . and not that
he should be converted and live?' Cf. Ezech. 33:11]: while it is a
false opinion that He refuses pardon to the repentant sinner, or that
He does not turn sinners to Himself by sanctifying grace. Therefore,
just as the movement of hope, which is in conformity with the true
opinion, is praiseworthy and virtuous, so the contrary movement of
despair, which is in conformity with the false opinion about God, is
vicious and sinful.

Reply Obj. 1: In every mortal sin there is,