Joshua 8:1-3

Then the LORD said to Joshua, “Don’t be afraid or give up. Lead all your fighting men to Ai. I will help you defeat the king of Ai, his people, his city, and his land. You will do to Ai and its king what you did to Jericho and its king. Only this time you may take all the wealth and keep it for yourselves. Now tell some of your soldiers to set up an ambush behind the city.” So Joshua led his whole army toward Ai. Then he chose thirty thousand of his best fighting men and sent them out at night.