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, ¹  as far as the Arnon.

Numbers 21:34

21:34 And the Lord said to Moses, “Do not fear him, for I have delivered him and all his people and his land into your hand. You will do to him what you did to King Sihon of the Amorites, who lived in Heshbon.

Numbers 32:33

Land Assignment

32:33 So Moses gave to the Gadites, the Reubenites, and to half the tribe of Manasseh son of Joseph the realm of King Sihon of the Amorites, and the realm of King Og of Bashan, the entire land with its cities and the territory surrounding them. ² 

[21:26]  ¹ sn There is a justice, always, in the divine plan for the conquest of the land. Modern students of the Bible often think that the conquest passages are crude and unjust. But an understanding of the ancient Near East is critical here. This Sihon was not a part of the original population of the land. He himself invaded the territory and destroyed the population of Moab that was indigenous there and established his own kingdom. The ancient history is filled with such events; it is the way of life they chose – conquer or be conquered. For Israel to defeat them was in part a turning of their own devices back on their heads – “those that live by the sword will die by the sword.” Sihon knew this, and he did not wait, but took the war to Israel. Israel wanted to pass through, not fight. But now they would either fight or be pushed into the gorge. So God used Israel to defeat Sihon, who had no claim to the land, as part of divine judgment.

[32:33]  ² tn Heb “the land with its cities in the borders of the cities of the land all around.”