“But as for the cities that stood still in their strength, Israel burned none of them, save Hazor only; that did Joshua burn.”
King James Version (KJV)
11:13 In their strength - Heb. with their fence, walls or bulwarks, that is, which were not ruined with their walls in taking them. Save Hazor - Because this city began the war, and being the chief and royal city, might renew the war. If the Canaanites should ever seize upon it: which in fact they did, and settled there, under a king of the same name, #Judges 4:2|.