Deuteronomy 2:31-37 -

God had determined to give Sihon and his land to the Israelites, and so certainly should this be done, that Moses is exhorted already to begin to seize, in order to possess the land. Sihon initiated hostilities by coming out with all his host to fight against Moses and the Israelites. The battle took place at Jahaz (or Jahazah, or Jahza), a town between Medeba and Dibon (Euseb.; cf. Numbers 33:45 ), afterwards belonging to the tribe of Reuben ( Joshua 13:18 ), and assigned to the Levites of the line of Merari ( Joshua 21:36 ; 1 Chronicles 6:78 ). The war was one of extermination, in which all the people of Sihon were destroyed, from one cad of his dominion to the other; all his cities were devoted irredeemably (comp. Le 27:29), and only the cattle and the material property were preserved as booty by the conquerors ( Numbers 21:23-26 ).