gh the heretic's sin is more
grave generically, it can be lessened by a circumstance, and
conversely the sin of the Catholic can, by some circumstance, be
aggravated.

Reply Obj. 2: Unbelief includes both ignorance, as an accessory
thereto, and resistance to matters of faith, and in the latter
respect it is a most grave sin. In respect, however, of this
ignorance, it has a certain reason for excuse, especially when a
man sins not from malice, as was the case with the Apostle.

Reply Obj. 3: An unbeliever is more severely punished for his sin of
unbelief than another sinner is for any sin whatever, if we consider
the kind of sin. But in the case of another sin, e.g. adultery,
committed by a believer, and by an unbeliever, the believer, other
things being equal, sins more gravely than the unbeliever, both on
account of his knowledge of the truth through faith, and on account
of the sacraments of faith with which he has been satiated, and
which he insults by committing sin.
_______________________

FOURTH ARTICLE [II-II, Q. 10, Art. 4]

Whether Every Act of an Unbeliever Is a Sin?

Objection 1: It would seem that each act of an unbeliever is a sin.
Because a gloss on Rom. 14:23, "All that is not of faith is sin,"
says: "The whole life of unbelievers is a sin." Now the life of
unbelievers consists of their actions. Therefore every action of an
unbeliever is a sin.

Obj. 2: Further, faith directs the intention. Now there can be no
good save what comes from a right intention. Therefore, among
unbelievers, no action can be good.

Obj. 3: Further, when that which precedes is corrupted, that which
follows is corrupted also. Now an act of faith precedes the acts of
all the virtues. Therefore, since there is no act of faith in
unbelievers, they can do no good work, but sin in every action of
theirs.

_On the contrary,_ It is said of Cornelius, while yet an unbeliever
(Acts 10:4, 31), that his alms were acceptable to God. Therefore not
every action of an unbeliever is a sin, but some of his actions are
good.

_I answer that,_ As stated above (I-II, Q. 85, AA. 2, 4) mortal sin
takes away sanctifying grace, but does not wholly corrupt the good of
nature. Since therefore, unbelief is a mortal sin, unbelievers are
without grace indeed, yet some good of nature remains in them.
Consequently it is evident that unbelievers cannot do those good works
which proceed from grace, viz. meritorious works; yet they can, to a
certain