Numbers 21:13-14
21:13 From there they moved on and camped on the other side of the Arnon, in the wilderness that extends from the regions of the Amorites, for Arnon is the border of Moab, between Moab and the Amorites.
21:14 This is why it is said in the Book of the Wars of the Lord, “Waheb in Suphah and the wadis,
the Arnon
Numbers 21:24
21:24 But 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.
Numbers 21:26
21:26 For Heshbon was the city of King Sihon of the Amorites. Now he had fought against the former king of Moab and had taken all of his land from his control, as far as the Arnon.