The military was not necessarily a state function over against a Church function in the Old Covenant. Holy war was a specifically priestly function. The torching of cities is to be understood as taking God's fire off from His altar and applying His holy fiery wrath to his enemies. Thus, the torched cities were called "whole burnt sacrifices" in the Hebrew Old Testament (Deut. 13:16; Judg. 1:17, 20:40, in Hebrew). During the holy war, the men became temporary priests by taking the Nazirite vow (Num. 6; 2 Sam. 11:11; Exo. 19:15; Deut. 23:9-14; Judg. 5:2). In short, the rendering of specific judgments is a sabbatical and priestly function, not a kingly one. The sword of the state executes according to the judgments rendered by the priests. (In the New Covenant age, every believer is a priest, just as the Old Covenant believers became priests by taking the Nazirite vow. In our system, the priests render judgment by sitting on a jury, and then the state executes the judgment.) Thus, the military duty is priestly, and a duty of every believer-priest. Both Church and state are involved in it, since the Church must say whether the war is just and holy, and the state must organize the believer-priests for battle.
- James Jordan, The Law of the Covenant 231-32 (1984), at http://www.garynorth.com/freebooks/: HTML, DjVu.