Judg 2:21

“Divine grace ever stirs up the will of human beings, not so as to protect and defend it in all things in such a way as to cause it not to fight by its own efforts against its spiritual adversaries, the victor over whom may set it down to God's grace, and the vanquished to his own weakness, and thus learn that his hope is always not in his own courage but in the divine assistance and that he must ever fly to his Protector. And to prove this not by our own conjecture but by still clearer passages of holy Scripture let us consider what we read in Joshua the son of Nun: "The Lord," it says, "left these nations and would not destroy them, that by them he might test Israel, whether they would keep the commandments of the Lord their God, and that they might learn to fight with their enemies." And if we may illustrate the incomparable mercy of our Creator from something earthly, not as being equal in kindness but as an illustration of mercy: if a tender and anxious nurse carries an infant in her bosom for a long time in order sometime to teach it to walk, and first allows it to crawl, then supports it that by the aid of her right hand it may lean on its alternate steps, presently leaves it for a little and if she sees it tottering at all, catches hold of it and grabs at it when falling, when down picks it up, and either shields it from a fall or allows it to fall lightly, and sets it up again after a tumble, but when she has brought it up to boyhood or the strength of youth or early manhood, lays upon it some burdens or labors by which it may be not overwhelmed but exercised, and allows it to vie with those of its own age; how much more does the heavenly Father of all know whom to carry in the bosom of his grace, whom to train to virtue in his sight by the exercise of free will, and yet he helps him in his efforts, hears him when he calls, leaves him not when he seeks him, and sometimes snatches him from peril even without his knowing it.”

“Nations. Hebrew, “any.” Septuagint, “a man of those nations,” which must be understood, unless the Israelites return to a proper sense of their duty. For then he destroyed not only individuals, but whole armies, by the hand of the judges. Yet we do not find that such havoc was made among the infidels afterwards, as had been made in the days of Josue. They frequently rose up and harassed the Israelites; and God suffered them to do so, that the latter might learn to know themselves, and might perceive how dreadful a thing it is not to comply, at first, with his injunctions. (Haydock)”