10 When thou approachest unto a city to fight against it, thou shalt proclaim peace unto it. 11 And it shall be, if it make thee answer of peace, and open unto thee, then all the people that are found therein shall be tributaries unto thee, and they shall serve thee. 12 And if it will not make peace with thee, but will make war with thee, then thou shalt besiege it; 13 and when Jehovah thy God delivereth it into thy hand, thou shalt smite every male thereof with the edge of the sword: 14 only the women, and the little ones, and the cattle, and all that shall be in the city, all the spoil thereof, shalt thou take as booty for thyself; and thou shalt eat the spoil of thine enemies, which Jehovah thy God giveth thee 15 Thus shalt thou do unto all the cities that are very far off from thee, which are not of the cities of these nations. 16 But of the cities of these peoples which Jehovah thy God giveth thee for an inheritance, thou shalt save alive nothing that breatheth, 17 but shalt utterly devote them to destruction, the Hittites and the Amorites, the Canaanites and the Perizzites, the Hivites and the Jebusites, as Jehovah thy God hath commanded thee; 18 that they teach you not to do according to all their abominations, which they have done unto their gods, so that ye sin against Jehovah your God.

Matthew Henry's Commentary on Deuteronomy 20:10-18

Commentary on Deuteronomy 20:10-12

(Read Deuteronomy 20:10-12)

The Israelites are here directed about the nations on whom they made war. Let this show God's grace in dealing with sinners. He proclaims peace, and beseeches them to be reconciled. Let it also show us our duty in dealing with our brethren. Whoever are for war, we must be for peace. Of the cities given to Israel, none of their inhabitants must be left. Since it could not be expected that they should be cured of their idolatry, they would hurt Israel. These regulations are not the rules of our conduct, but Christ's law of love. The horrors of war must fill the feeling heart with anguish upon every recollection; and are proofs of the wickedness of man, the power of Satan, and the just vengeance of God, who thus scourges a guilty world. But how dreadful their case who are engaged in unequal conflict with their Maker, who will not submit to render him the easy tribute of worship and praise! Certain ruin awaits them. Let neither the number nor the power of the enemies of our souls dismay us; nor let even our own weakness cause us to tremble or to faint. The Lord will save us; but in this war let none engage whose hearts are fond of the world, or afraid of the cross and the conflict. Care is here taken that in besieging cities the fruit-trees should not be destroyed. God is a better friend to man than he is to himself; and God's law consults our interests and comforts; while our own appetites and passions, which we indulge, are enemies to our welfare. Many of the Divine precepts restrain us from destroying that which is for our life and food. The Jews understand this as forbidding all wilful waste upon any account whatsoever. Every creature of God is good; as nothing is to be refused, so nothing is to be abused. We may live to want what we carelessly waste.