Joshua 8:3
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.
Cross-reference
Joshua 8:12
Parallel
In Joshua 8:12, a second ambush of 5,000 men complements the 30,000 sent in verse 3, part of the same battle plan.
Joshua 8:17
Parallel
In Joshua 8:17, all Ai's men pursue Israel, fulfilling the plan from verse 3 to draw them out.