Numbers 21:26 (KJV)

And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon was strong.

And Israel took all these cities: and Israel dwelt in all the cities of the Amorites, in Heshbon, and in all the villages thereof.

For Heshbon was the city of Sihon the king of the Amorites, who had fought against the former king of Moab, and taken all his land out of his hand, even unto Arnon.

Wherefore they that speak in proverbs say, Come into Heshbon, let the city of Sihon be built and prepared:

For there is a fire gone out of Heshbon, a flame from the city of Sihon: it hath consumed Ar of Moab, and the lords of the high places of Arnon.