On the contrary, stands the authority of Scripture.
I answer that, In one who is being instructed in virtue it is necessary to remove obstacles to true religion before establishing him in true religion. Now a thing is opposed to true religion in two ways. First, by excess, when, to wit, that which belongs to religion is given to others than to whom it is due, and this pertains to superstition. Secondly, by lack, as it were, of reverence, when, to wit, God is contemned, and this pertains to the vice of irreligion, as stated above (Q. 97, in the preamble, and in the Article that follows). Now superstition hinders religion by preventing man from acknowledging God so as to worship Him: and when a man's mind is engrossed in some undue worship, he cannot at the same time give due worship to God, according to Isa. 28:20, "The bed is straitened, so that one must fall out," i.e. either the true God or a false god must fall out from man's heart, "and a short covering cannot cover both." On the other hand, irreligion hinders religion by preventing man from honoring God after he has acknowledged Him. Now one must first of all acknowledge God with a view to worship, before honoring Him we have acknowledged.
For this reason the precept forbidding superstition is placed before the second precept, which forbids perjury that pertains to irreligion.
Reply Obj. 1: These expositions are mystical. The literal explanation is that which is given Deut. 5:11: "Thou shalt not take the name of . . . thy God in vain," namely, "by swearing on that which is not [*Vulg.: 'for he shall not be unpunished that taketh 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?