Numbers 31:4-6

4You shall send a thousand from each tribe of all the tribes of Israel to the war.”

5So there were selected from the thousands of Israel, a thousand from each tribe, twelve thousand armed for war.

6And Moses sent them, a thousand from each tribe, to the war, and Phinehas the son of Eleazar the priest, to the war with them, 1and the holy implements and 2the trumpets for the alarm in his hand.