Numbers 31:4-6

American Standard Version

⁴ Of every tribe a thousand, throughout all the tribes of Israel, shall ye send to the war. ⁵ So there were delivered, out of the thousands of Israel, a thousand of every tribe, twelve thousand armed for war. ⁶ And Moses sent them, a thousand of every tribe, to the war, them and Phinehas the son of Eleazar the priest, to the war, with the vessels of the sanctuary and the trumpets for the alarm in his hand.