Exodus 23

13. Make no mention of the name of other gods. There is no sort of doubt but that this declaration should be connected with the Third Commandment. Moses explains that God's name is taken in vain and abused, if men swear by other gods; for it is not lawful to refer the judgment of things unknown to any other than the one true God. Consequently, the glory of the Deity is transferred to those by whose name men swear. Therefore by the Prophet God pronounces a severe denunciation, that He will destroy all those that swear by His name, and also by Malcham, (Zephaniah 1:5,) since thus the Jews mixed Him up with their idol, and so profaned His holiness. In sum, since by swearing we profess that He is our God, whom we declare to be both the knower of our hearts and the judge of our souls, the true God justly claims this honor for Himself alone, inasmuch as the glory of His name is detracted from, not only if we speak less reverently than we should of Him, but also if we associate with Him such as may usurp a part of His rights. And this more clearly appears from the two passages which we have adduced from Deuteronomy, wherein the people are commanded to swear by the name of the one God, which is equivalent to rendering to His sacred name in our outward profession of service the unmixed reverence which it deserves. ¹ Still God does not exhort the people to indulge themselves freely in oaths, as if by frequent oaths they exercised themselves in the duties of piety, but simply means that when there is occasion for it or necessity, and a just cause shall demand it, they must swear in no other way than by invoking Him alone as their witness and judge.