the good and evil of which we are speaking now are
differences of the moral act. Now differences make an essential
division in a genus, according to the Philosopher (Metaph. vii, 12).
Since therefore an act is moral from being voluntary, it seems that
goodness and malice in an act are derived from the will alone.

_On the contrary,_ Augustine says (Contra Mendac. vii), that "there
are some actions which neither a good end nor a good will can make
good."

_I answer that,_ As stated above (A. 1), we may consider a twofold
goodness or malice in the external action: one in respect of due
matter and circumstances; the other in respect of the order to the
end. And that which is in respect of the order to the end, depends
entirely on the will: while that which is in respect of due matter or
circumstances, depends on the reason: and on this goodness depends
the goodness of the will, in so far as the will tends towards it.

Now it must be observed, as was noted above (Q. 19, A. 6, ad 1), that
for a thing to be evil, one single defect suffices, whereas, for it
to be good simply, it is not enough for it to be good in one point
only, it must be good in every respect. If therefore the will be
good, both from its proper object and from its end, if follows that
the external action is good. But if the will be good from its
intention of the end, this is not enough to make the external action
good: and if the will be evil either by reason of its intention of
the end, or by reason of the act willed, it follows that the external
action is evil.

Reply Obj. 1: If the good tree be taken to signify the good will, it
must be in so far as the will derives goodness from the act willed
and from the end intended.

Reply Obj. 2: A man sins by his will, not only when he wills an evil
end; but also when he wills an evil act.

Reply Obj. 3: Voluntariness applies not only to the interior act of
the will, but also to external actions, inasmuch as they proceed from
the will and the reason. Consequently the difference of good and evil
is applicable to both the interior and external act.
________________________

THIRD ARTICLE [I-II, Q. 20, Art. 3]

Whether the Goodness and Malice of the External Action Are the Same
As Those of the Interior Act?

Objection 1: It would seem that the goodness and malice of the
interior act of the will are not the same as those of the external
action. For the principle of the interior act is the interior
apprehen