John Gill Bible Commentary

Perhaps at her first approach to him, and attempt to drive the nail, or at the blow she gave, he rose up, but she had done the business so effectually at the first stroke, that he dropped at once, and laid down his head again: at her feet he bowed, he fell; when she redoubled her blow: where he bowed, there he fell down dead; and struggled and stirred no more; thus ingloriously did this general of a vast army die. This action is not otherwise to be justified, but by its being done through an impulse of the Spirit of God upon her, to take away the life of an implacable enemy of God's people; otherwise it might seem to be a breach of hospitality towards her guest she had invited in, and of the peace which subsisted between this general's prince and her husband; and therefore is not to be drawn into an example where there is no appearance of a divine warrant.