Numbers 21:26-28

26 Heshbon was the city of Sihon king of the Amorites, who had fought against the former king of Moab and had taken from him all his land as far as the Arnon.

27 That is why the poets say:
“Come to Heshbon and let it be rebuilt;
let Sihon’s city be restored.

28 “Fire went out from Heshbon,
a blaze from the city of Sihon.
It consumed Ar of Moab,
the citizens of Arnon’s heights.