20:1-9 In the wars wherein Israel engaged according to the will of God, they might expect the Divine assistance. The Lord was to be their only confidence. In these respects they were types of the Christian's warfare. Those unwilling to fight, must be sent away. The unwillingness might arise from a man's outward condition. God would not be served by men forced against their will. Thy people shall be willing, Ps 110:3. In running the Christian race, and fighting the good fight of faith, we must lay aside all that would make us unwilling. If a man's unwillingness rose from weakness and fear, he had leave to return from the war. The reason here given is, lest his brethren's heart fail as well as his heart. We must take heed that we fear not with the fear of them that are afraid, Isa 8:12.

5-8. And the officers shall speak unto the people—literally, Shoterim, who are called "scribes" or "overseers" (Ex 5:6). They might be keepers of the muster-roll, or perhaps rather military heralds, whose duty it was to announce the orders of the generals (2Ch 26:11). This proclamation (De 20:5-8) must have been made previous to the priest's address, as great disorder and inconvenience must have been occasioned if the serried ranks were broken by the departure of those to whom the privilege was granted. Four grounds of exemption are expressly mentioned: (1) The dedication of a new house, which, as in all Oriental countries still, was an important event, and celebrated by festive and religious ceremonies (Ne 12:27); exemption for a year. (2) The planting of a vineyard. The fruit of the first three years being declared unfit for use, and the first-fruits producible on the fourth, the exemption in this case lasted at least four years. (3) The betrothal of a wife, which was always a considerable time before marriage. It was deemed a great hardship to leave a house unfinished, a new property half cultivated, and a recently contracted marriage; and the exemptions allowed in these cases were founded on the principle that a man's heart being deeply engrossed by something at a distance, he would not be very enthusiastic in the public service. (4) The ground of exemption was cowardice. From the composition of the Israelitish army, which was an irregular militia, all above twenty years being liable to serve, many totally unfit for war must have been called to the field; and it was therefore a prudential arrangement to rid the army of such unwarlike elements—persons who could render no efficient service, and the contagion of whose craven spirit might lead to panic and defeat.