Numbers 31:2-4

New Revised Standard Version, Anglicised Catholic Edition

² ‘Avenge the Israelites on the Midianites; afterwards you shall be gathered to your people.’ ³ So Moses said to the people, ‘Arm some of your number for the war, so that they may go against Midian, to execute the Lord’s vengeance on Midian. ⁴ You shall send a thousand from each of the tribes of Israel to the war.’