Numbers 21:23-25

23But Sihon did not permit Israel to pass through his border; he gathered all his forces together and went out against Israel into the wilderness. When he came to Jahaz, he fought against Israel.

24But the Israelites defeated him in battle and took possession of his land from the Arnon to the Jabbok, as far as the Ammonites, for the border of the Ammonites was strongly defended.

25So Israel took all these cities; and Israel settled in all the cities of the Amorites, in Heshbon, and in all its villages.