Then Sihon came out against us,.... Perceiving they were upon their march towards his land or into it, he gathered all his people and went out of Heshbon their capital city, where he resided: he and all his people, to fight at Jahaz; a city which he had taken from the king of Moab, and which in later times, after the captivity of the ten tribes, came into their hands again, Isa 15:4; see Gill on Num 21:21.