h His
name upon a vain thing']."

Reply Obj. 2: This precept does not forbid all taking of the name of
God, but properly the taking of God's name in confirmation of a man's
word by way of an oath, because men are wont to take God's name more
frequently in this way. Nevertheless we may understand that in
consequence all inordinate taking of the Divine name is forbidden by
this precept: and it is in this sense that we are to take the
explanation quoted in the First Objection.

Reply Obj. 3: To swear to nothing means to swear to that which is
not. This pertains to false swearing, which is chiefly called
perjury, as stated above (Q. 98, A. 1, ad 3). For when a man swears
to that which is false, his swearing is vain in itself, since it is
not supported by the truth. On the other hand, when a man swears
without judgment, through levity, if he swear to the truth, there is
no vanity on the part of the oath itself, but only on the part of the
swearer.

Reply Obj. 4: Just as when we instruct a man in some science, we
begin by putting before him certain general maxims, even so the Law,
which forms man to virtue by instructing him in the precepts of the
decalogue, which are the first of all precepts, gave expression, by
prohibition or by command, to those things which are of most common
occurrence in the course of human life. Hence the precepts of the
decalogue include the prohibition of perjury, which is of more
frequent occurrence than blasphemy, since man does not fall so often
into the latter sin.

Reply Obj. 5: Reverence is due to the Divine names on the part of the
thing signified, which is one, and not on the part of the signifying
words, which are many. Hence it is expressed in the singular: "Thou
shalt not take the name of . . . thy God in vain": since it matters
not in which of God's names perjury is committed.
_______________________

FOURTH ARTICLE [II-II, Q. 122, Art. 4]

Whether the Third Precept of the Decalogue, Concerning the Hallowing
of the Sabbath, Is Fittingly Expressed?

Objection 1: It seems that the third precept of the decalogue,
concerning the hallowing of the Sabbath, is unfittingly expressed.
For this, understood spiritually, is a general precept: since Bede in
commenting on Luke 13:14, "The ruler of the synagogue being angry
that He had healed on the Sabbath," says (Comment. iv): "The Law
forbids, not to heal man on the Sabbath, but to do servile works,"
i.e. "to burden oneself with sin." Tak