Four things catch my attention when reading Deuteronomy 20:
First, that the chapter is devoted to instructions about war. In fact, you will find a lot of instructions about going to war in today’s and tomorrow’s readings (through chapter 25). The fact was, war was to be a way of life for God’s people – not because they were to be a people of aggression, but because the world around Israel would not leave God’s people in peace. As much as it lies with us, we must live in peace – with one another and toward the world. The world is not our enemy. Our enemy is Satan, not the people he has deceived. On the other hand, because Satan is our enemy, we should never expect that the world will live at peace with us.
Second, I wonder how God’s people were supposed to populate an army. It looks like everyone had an exemption: newlyweds, newly engaged, new home owners, new land holders, and those who were simply afraid to go to war. All were excluded from military service. The answer, of course, is that the size of the army did not matter: God would give the victory. But think about the reasons involved. First, marriage. It is such an important commitment that once approached, God would grant special accommodation to assure its success. Second, dedication. Houses, and the homes within them, were dedicated to the Lord. This too was important. New fields were not to be eaten from for four years, dedicating their harvest to God. God would not be denied. And finally, the afraid. Faithlessness is contagious. God would not permit such among His troops.
Third, note the difference between how Israel prosecutes war in different places: Within her borders, no quarter was given. Her enemies were to be utterly destroyed. Outside those borders however, quarter was to be given and rules followed about who could be taken prisoner and how they were to be treated. Why the difference? God lays it at the door of the Canaanites. They were wicked people and this was His holy ground. Wickedness was not to be tolerated.
The last thing has to do with trees. Food producing plants were to be regarded differently than non-producing. But the bottom line is that the earth is the Lord’s. A “scorched earth” policy in war was simply inappropriate for the people of God.