Adam Clarke on 2 Kings 19:25

Hast thou not heard - Here Jehovah speaks, and shows this boasting king that what he had done was done by the Divine appointment, and that of his own counsel and might he could have done nothing. It was because God had appointed them to this civil destruction that he had overcome them; and it was not through his might; for God had made their inhabitants of small power, so that he only got the victory over men whom God had confounded, dismayed, and enervated, 2Kgs 19:26.