Numbers 31:4 KJV

2Avenge the children of Israel of the Midianites: afterward shalt thou be gathered unto thy people.

3And 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.

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

5So there were delivered out of the thousands of Israel, a thousand of every tribe, twelve thousand armed for war.

6And Moses sent them to the war, a thousand of every tribe, them and Phinehas the son of Eleazar the priest, to the war, with the holy instruments, and the trumpets to blow in his hand.