Numbers 21:26 - Clarke's commentary and critical notes on the Bible

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, even unto Arnon. For Heshbon was the city of Sihon, etc. - It appears therefore that the territory now taken from Sihon by the Israelites was taken from a former king of Moab, in commemoration of which an epikedion or war song was made, several verses of which, in their ancient poetic form, are here quoted by Moses.