Numbers 21:21-25, 35

Then Israel sent messengers to Sihon king of the Amorites, saying, “Let me pass through your land. We will not turn aside into field or vineyard. We will not drink the water of a well. We will go by the King’s Highway until we have passed through your territory.” But Sihon would not allow Israel to pass through his territory. He gathered all his people together and went out against Israel to the wilderness and came to Jahaz and fought against Israel. And Israel defeated him with the edge of the sword and took possession of his land from the Arnon to the Jabbok, as far as to the Ammonites, for the border of the Ammonites was strong. And Israel took all these cities, and Israel settled in all the cities of the Amorites, in Heshbon, and in all its villages.

So they defeated him and his sons and all his people, until he had no survivor left. And they possessed his land.