He speaks according to their fond and absurd opinion. The Ammonites and Moabites got their land by right of war, and conquest of the old inhabitants, whom they cast out; and this success, though given them by the true God, for Lot's sake, Deuteronomy 2:19, they impiously and ridiculously ascribe to their god Chemosh, whose gift they owned to be a firm and sufficient title.
Related Commentaries of Judges 11:24
Judges 11:24
24 Wilt not thou possess that which Chemosh thy god giveth thee to possess? So whomsoever the LORD our God shall drive out from before us, them will we possess.