At that time we captured all his cities and devoted to destruction the people of every city, including women and children. We left no survivors.
God having tried the self-denial of his people in forbidding them to meddle with the Moabites and Ammonites, and they having quietly passed by those rich countries, and, though superior in number, not made any attack upon them, here he recompenses them for their obedience by giving them possession of the country of Sihon king of the Amorites.
Commenting on Deuteronomy 2:24-37
And we took all his cities at that time,.... As Heshbon, and others mentioned in Num 21:25, and utterly destroyed the men, and the women, and the little ones of every city, we left none to remain; for the Amorites were one of the seven nations who were devoted to destruction, the measure of whose iniquity was now full, and therefore vengeance was taken.
And we took all his cities at that time, and utterly destroyed the men, and the women, and the little ones, of every city, we left none to remain: (o) God had cursed Canaan, and therefore he did not want any of the wicked race to be preserved.