Deuteronomy 20:9
And it shall be, when the officers have made an end of speaking unto the people that they shall make captains of the armies to lead the people. (Deuteronomy 20:9)
Captains.
 Referring to officers in command of companies of thousands, hundreds, or fifties (see Num. 31:14, 48; 1 Sam. 8:12; 22:7; 2 Sam. 18:1). The singular number, captain of a “host,” is used to designate the commander in chief of the entire army (Gen. 21:22; 2 Sam. 2:8; 1 Kings 16:16).