"The Lord Yahweh has sworn by himself," says Yahweh, the God of hosts: "I abhor the pride of Jacob, And detest his fortresses. Therefore I will deliver up the city with all that is in it.
But that this threatening might not be slighted, the Prophet confirms it by interposing an oath. Hence he says, that God had sworn. And as we know that God’s name is precious to him, it is certain that it was not in vain adduced here, but on account of the hardness and contumacy of those who were wont to set at nought all the prophecies, and were wont in particular to regard as nothing all threatenings. This was the reason why the Prophet wished thus to ratify what he had said: it was, that hypocrites might understand that they could not escape the vengeance which he had denounced. The form of swearing, as it is, may seem apparently improper; but God in this place puts on the character of man, as he does often in other places. He swears by his soul, that is, by his life, as though he were one of mankind. But we ought to accustom ourselves to such forms, in which God familiarly accommodates himself to our capacities: for what Hilary philosophizes about the soul, as though God the Father swore by his own wisdom, is frivolous: that good man certainly exposed his own doctrine to ridicule, while he was attempting to refute the Arians. “God the Father, he says, swears by his own wisdom. Now he who is wont to swear by himself, could not swear by an inferior; but wisdom is the only begotten Son of God: hence it follows, that the Son is equal to the Father.” These things at first sight seem plausible; but they are puerile trifles. 