hich is
deposited with another man burdens the depositary, who is bound
either to restitution, or to prove himself innocent. Hence he is
clearly guilty of sin, and is bound to ease the depositary of his
burden. On the other hand he who, by stealth, takes his own property,
if this be unjustly detained by another, he sins indeed; yet not
because he burdens the retainer, and so he is not bound to
restitution or compensation: but he sins against general justice by
disregarding the order of justice and usurping judgment concerning
his own property. Hence he must make satisfaction to God and endeavor
to allay whatever scandal he may have given his neighbor by acting
this way.
_______________________

SIXTH ARTICLE [II-II, Q. 66, Art. 6]

Whether Theft Is a Mortal Sin?

Objection 1: It would seem that theft is not a mortal sin. For it is
written (Prov. 6:30): "The fault is not so great when a man hath
stolen." But every mortal sin is a great fault. Therefore theft is
not a mortal sin.

Obj. 2: Further, mortal sin deserves to be punished with death. But
in the Law theft is punished not by death but by indemnity, according
to Ex. 22:1, "If any man steal an ox or a sheep . . . he shall
restore have oxen for one ox, and four sheep for one sheep."
Therefore theft is not a mortal sin.

Obj. 3: Further, theft can be committed in small even as in great
things. But it seems unreasonable for a man to be punished with
eternal death for the theft of a small thing such as a needle or a
quill. Therefore theft is not a mortal sin.

_On the contrary,_ No man is condemned by the Divine judgment save
for a mortal sin. Yet a man is condemned for theft, according to
Zech. 5:3, "This is the curse that goeth forth over the face of the
earth; for every thief shall be judged as is there written."
Therefore theft is a mortal sin.

_I answer that,_ As stated above (Q. 59, A. 4; I-II, Q. 72, A. 5), a
mortal sin is one that is contrary to charity as the spiritual life
of the soul. Now charity consists principally in the love of God, and
secondarily in the love of our neighbor, which is shown in our
wishing and doing him well. But theft is a means of doing harm to our
neighbor in his belongings; and if men were to rob one another
habitually, human society would be undone. Therefore theft, as being
opposed to charity, is a mortal sin.

Reply Obj. 1: The statement that theft is not a great fault is in
view of two cases. First, when a person is