Numbers 31:4-6

Amplified Bible

⁴ A thousand [fighting men] from each tribe of all the tribes of Israel you shall send to the war.” ⁵ So out of the thousands of Israel, a thousand from each tribe were selected, twelve thousand armed for war. ⁶ Moses sent them, a thousand from each tribe, to the war, and Phinehas the son of Eleazar the priest, to war with them, and the sacred vessels [of the sanctuary] and the trumpets to blow the alarm in his hand.