Jos 8:2
Joshua was to do the same to Ai and her king as he had already done to Jericho and her king, except that in this case the conquerors were to be allowed to appropriate the booty and the cattle to themselves. In order to conquer the town, he was to lay an ambush behind it. ארב, a collective noun, signifying the persons concealed in ambush; מארב (Jos 8:9), the place of ambush. “Behind it,” i.e., on the west of the town.