Numbers 31:2-4

American Standard Version

² Avenge the children of Israel of the Midianites: afterward shalt thou be gathered unto thy people. ³ And Moses spake unto the people, saying, Arm ye men from among you for the war, that they may go against Midian, to execute Jehovah’s vengeance on Midian. ⁴ Of every tribe a thousand, throughout all the tribes of Israel, shall ye send to the war.