And thou shalt do to Ai and her king as thou didst unto Jericho and her king: only the spoil thereof, and the cattle thereof, shall ye take for a prey unto yourselves: lay thee an ambush for the city behind it.
And you should treat Ai and its king just like you did Jericho and its king. But only take the valuables and animals from Ai for yourself. Set a hidden group to attack the city from behind.