Joshua 8:3 in the King James Version
So Joshua arose, and all the people of war, to go up against Ai: and Joshua chose out thirty thousand mighty men of valour, and sent them away by night.
Context
2 You shall do to Ai and her king as you did to Jericho and her king, except you shall take its goods and its livestock for yourselves. Set an ambush for the city behind it.”
3 So Joshua arose, with all the warriors, to go up to Ai. Joshua chose thirty thousand men, the mighty men of valor, and sent them out by night.
4 He commanded them, saying, “Behold, you shall lie in ambush against the city, behind the city. Don’t go very far from the city, but all of you be ready.