24. The Lord of hosts hath sworn. For more full confirmation an oath was necessary. There is nothing of which it is more difficult to convince us than that wicked men will immediately be ruined, when we see them flourishing, and furnished with all means of defense, and seemingly placed out of danger, and free from all fear. We are therefore stunned by beholding them, and are dazzled by their brightness, so that we can scarcely believe God when he foretells their ruin and destruction. On this account he employs an oath, that he may leave no room for doubt. Hence we learn how great is his forbearance towards us, when he aids our weakness by applying this remedy, for otherwise he might have been satisfied with simply declaring it. This tends to the consolation of the godly, as we shall afterwards see. (Isaiah 22:14.)
If it hath not been as I thought. The elliptical form of an oath which he employs must be well known, for it occurs frequently in Scripture. The Lord purposely used this guarded language, that we might not be too free in the use of oaths, which burst from us daringly and at random. He suppresses the greater part of the oath. “If I shall not do what I have decreed, let men think that I am a liar, and let them not think that I am God;” or something of this kind (which we shudder to express) is left to be supplied. Men ought, therefore, to lay a bridle on themselves, so as not to break out at random into imprecations, or to pronounce shocking curses against themselves; but let them learn from this to restrain their insolence.