And ye shall not swear by my name falsely. Although Moses is treating of the duties of the Second Table, and had previously forbidden men to deal fraudulently with their neighbors, he still adds this sentence by way of confirmation. It may, however, be inferred from the second clause of the verse that He directly had regard to the glory of God when he says, "Thou shalt not profane the name of thy God." For raging greediness after gain causes the avaricious and rapacious man not only to defraud men, but to become insolent to God Himself. Moses, therefore, although he is professedly condemning the falsehood and deceit whereby our neighbors are injured, at the same time takes occasion to introduce the declaration that we must beware lest, whilst covetousness impels us to do wrong, injury should be done not only to men but to God Himself also. The word used here, however, is not sv', shau, as before, but sqr, sheker, which properly signifies deceitfulness; and therefore I have said that it enjoins us to beware lest any one by his perjury should do any injury to his neighbor; nevertheless, that this prohibition has direct reference to the Third Commandment, since Moses especially insists on this point, that God's name is profaned by perjury, and thus he not only inculcates integrity, but also has regard to religion, that God's majesty may not be violated. The expression is worthy of notice, "Thou shalt not pollute the name of God," because God, who is eternal and immutable truth, cannot be more grossly insulted than by being summoned as a witness to falsehood, which is assuredly a shameful and wicked pollution. This was not regarded by the heathen, who, although they pretended to reverence God's name in their oaths, yet made no scruple of deceiving, if he whom they had promised deserved it. Thyestes in the poet says, "I never have pledged my faith, nor do I pledge it to any faithless person;" [1] since his brother was a villain, he considered that he lay under no valid obligation to him. This is as if God's majesty were dependent upon men's deservings, so that it was allowable to call Him to witness whilst we deal deceitfully. Let this, then, be our firm conclusion, that in our oaths God is first to be regarded, whose holy name is more precious than a hundred worlds.

Footnotes

1 - Cic. de Off. 3 28, 29. "Deinde illud etiam apud Actium Fregisti fidem. Neque dedi neque do infideli cuiquam, quanquam ab impio rege dicitur, luculente tamen dicitur. "Nam illud quidem, Neque dedi, neque do fidem in fideli cuiquam, idcirco recte a poeta; quia, cum tractaretur Atreus, personae serviendum fuit."

And ye shall not swear by my name falsely,.... Or "to a falsehood" (x), to any of the above cases; as that a man has not the deposit of another's in his hands, when he has; or that such a man owes him so much money, when he does not, or any other false thing. Stealing, dealing falsely, lying, and false swearing, are mentioned together, as following one another, and as tending to lead on, the one to the other, as Jarchi observes;"if thou stealest, this will lead thee on to deal falsely, and then to lie, and after that to swear;''and who further remarks, because it may be thought a man is guilty only because of the proper name (of God he may swear by); therefore to comprehend all the surnames (or epithets of God, such as gracious, merciful, &c.) it is said, "ye shall not swear by, my name falsely": every name which is mine, by which he is called; and so Gersom, any epithet or attribute of his, or any word or phrase by which he is described, as he that made the heavens, or that dwelleth in the heavens, or liveth for ever and ever, and the like; and the word being of the plural number, ye shall not swear, takes in, as Aben Ezra thinks, him that causes to swear, as well as him that swears:
neither shall thou profane the name of thy God: through swearing falsely by it, or through any rash or vain oath in common conversation; not only perjury in a court of judicature, but all profane oaths, curses, and imprecations are forbidden, as breaches of the third command, which this refers to; See Gill on Exodus 20:7,
I am the Lord; whose name is holy, and who can and will revenge every abuse of it in a profane way, and to the injury of men.
(x) "ad fallaciam ullam", Junius & Tremellius, Piscator; so Ainsworth.

Ye shall not swear falsely - This is added, to shew how one sin draws on another, and that when men will lye for their own advantage, they will easily be induced to perjury. Profane the name - By any unholy use of it. So it is an additional precept, thou shalt not abuse my holy name by swearing either falsely or rashly.