Joshua 11:13-15

But Israel did not burn any of the cities that stood [walled and fortified] on their mounds, except Hazor alone, which Joshua burned. The sons of Israel took as their plunder all the spoil of these cities and the cattle; but they struck every man with the edge of the sword, until they had destroyed them. They left no one alive. Just as the LORD had commanded Moses His servant, so Moses had commanded Joshua, and so Joshua did; he left nothing undone of all that the LORD had commanded Moses.