, or that some utility might be
hindered, it was necessary to add a promise of reward. And since
parents are already on the way to depart from us, no benefit is
expected from them: wherefore a promise of reward is added to the
precept about honoring one's parents. The same applies to the precept
forbidding idolatry: since thereby it seemed that men were hindered
from receiving the apparent benefit which they think they can get by
entering into a compact with the demons.

Reply Obj. 4: Punishments are necessary against those who are prone
to evil, as stated in _Ethic._ x, 9. Wherefore a threat of punishment
is only affixed to those precepts of the law which forbade evils to
which men were prone. Now men were prone to idolatry by reason of the
general custom of the nations. Likewise men are prone to perjury on
account of the frequent use of oaths. Hence it is that a threat is
affixed to the first two precepts.

Reply Obj. 5: The commandment about the Sabbath was made in memory of
a past blessing. Wherefore special mention of the memory is made
therein. Or again, the commandment about the Sabbath has a
determination affixed to it that does not belong to the natural law,
wherefore this precept needed a special admonition.
________________________

EIGHTH ARTICLE [I-II, Q. 100, Art. 8]

Whether the Precepts of the Decalogue Are Dispensable?

Objection 1: It would seem that the precepts of the decalogue are
dispensable. For the precepts of the decalogue belong to the natural
law. But the natural law fails in some cases and is changeable, like
human nature, as the Philosopher says (Ethic. v, 7). Now the failure
of law to apply in certain particular cases is a reason for
dispensation, as stated above (Q. 96, A. 6; Q. 97, A. 4). Therefore a
dispensation can be granted in the precepts of the decalogue.

Obj. 2: Further, man stands in the same relation to human law as God
does to Divine law. But man can dispense with the precepts of a law
made by man. Therefore, since the precepts of the decalogue are
ordained by God, it seems that God can dispense with them. Now our
superiors are God's viceregents on earth; for the Apostle says (2
Cor. 2:10): "For what I have pardoned, if I have pardoned anything,
for your sakes have I done it in the person of Christ." Therefore
superiors can dispense with the precepts of the decalogue.

Obj. 3: Further, among the precepts of the decalogue is one
forbidding murder. But it seems that a di