Numbers 21:21-25
And Israel sent messengers to Sihon king of the Amorites, saying,
Nave's Topical Index—AKJV

Deuteronomy 2:24-37
Rise you up, take your journey, and pass over the river Arnon: behold, I have given into your hand Sihon the Amorite, king of Heshbon, and his land: begin to possess it, and contend with him in battle.
Nave's Topical Index—AKJV

Deuteronomy 3:2,6,8
And the LORD said to me, Fear him not: for I will deliver him, and all his people, and his land, into your hand; and you shall do to him as you did to Sihon king of the Amorites, which dwelled at Heshbon.
Nave's Topical Index—AKJV