Dueteronomy 20 10-14
10 When you march up to attack a city, make its people an offer of peace. 11 If they accept and open their gates, all the people in it shall be subject to forced labor and shall work for you. 12 If they refuse to make peace and they engage you in battle, lay siege to that city. 13 When the Lord your God delivers it into your hand, put to the sword all the men in it. 14 As for the women, the children, the livestock and everything else in the city, you may take these as plunder for yourselves. And you may use the plunder the Lord your God gives you from your enemies.
Military conduct/theology of God's people (20:1-20)As Yahweh's holy people, Israel must conduct warfare in a way pleasing to him. Holy warfare by Israel is described in this chapter as warfare in which only the will of Yahweh is to be done in the war.
The taking of Canaan from its inhabitants was not to be a land grab by a group of land-hungry descendants of Abraham, Isaac, and Jacob. Yahweh was giving it to Israel to fulfill his promises to the patriarchs. This holy war had a theological purpose. It was the fulfilling of Yahweh's promises, which involved establishment of an ethical-religious community of God's people in the land and judgment of the Canaanites through Israel.
War from this perspective by God's people is not possible today. Nor are God's people commanded to destroy their political, military, or religious enemies, but to love them. Because Yahweh conducted this war as a warrior (Ex 15:3, 7; see Lind) the biblical writer approves of it. God himself was involved with his people in the war to conquer Canaan.
God ordered the herem, the complete destruction of cities, to avoid the corruption of his people (vv. 16-18). This provision was necessary for two reasons.
First, the Canaanites were not going to change for the better, for Yahweh had allowed their cup of iniquity to become full (Ge 15:16). Later, because of its ethical-religious corruption under wicked kings, Israel would be treated no differently. When its cup of iniquity was full, God cast Israel out of the land to be punished by Assyrians and Babylonians.
Second, Israel was especially vulnerable at the early stages of her history, and the importance of impressing the people with the grave consequences of ethical-religious corruption in the land of the Amorites needed to be made. God's stringent procedures against Ananias and Sapphira at the outset of the new covenant people (Acts 5:1-11) closely parallels the principle of Dt 20. Because distant cities did not pose the threat of immediate ethical-religious contamination, they were not placed under the herem for complete destruction. Israel's conduct of war had to be carried out within the parameters of holy war prescribed by Yahweh and Yahweh alone.
Asbury Bible Commentary