Numbers 21:23

And Sihon would not suffer Israel to pass through his border; but Sihon gathered all his people together and went out against Israel into the wilderness, to drive out the invaders; and he came to Jahaz, a place in the southeastern part of his dominion, and fought against Israel. In this case, however, the children of Israel were not hindered by special considerations, as in the case of the Edomites, the Moabites, and the Ammonites, Deuteronomy 2:5; Deuteronomy 2:37, but had received the express command to give battle, Deuteronomy 2:24.