For Heshbon was the city of Sihon the king of the Amorites, who had fought against the former king of Moab and taken all his land out of his hand, as far as the Arnon.
26. For Heshbon was the city of Sihon. It is not without cause that Moses relates how the country near Heshbon had passed into the hands of the Amorites, because a long time afterwards this was sought for as a pretext for war by the Ammonites, when they saw that the people were brought into a low estate.
We have here an account of the victories obtained by Israel over Sihon and Og, which must be distinctly considered, not only because they are here distinctly related, but because long afterwards the memorial of them is distinctly celebrated, and they are severally assigned as instances of everlasting mercy.
Commenting on Numbers 21:21-35
Woe to thee, Moab! thou art undone,.... The whole country ruined, or likely to be so: O people of Chemosh; which was the name of their idol, who is called the abomination of the Moabites, Kg1 11:7, he hath given his sons that escaped; that is, the idol Chemosh had given his sons, the men of the country that worshipped him, who escaped the sword...