Numbers 31:2-4

King James 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 some of yourselves unto the war, and let them go against the Midianites, and avenge the Lord of Midian.

⁴ Of every tribe a thousand, throughout all the tribes of Israel, shall ye send to the war.