Verse 11. - Shall be tributaries unto thee, and they shall serve thee; literally, shall be to thee for tribute and service. The word rendered by "tribute" (מַם) denotes properly tribute service, service rendered as a tribute, whether for a season or in perpetuity (cf. Genesis 49:15; Judges 1:30, 33, 35; 1 Kings 5:13; 1 Kings 9:21; Isaiah 31:8 [Authorized Version, "discomfited"])

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.And it shall be, if it make thee answer of peace,.... Comply with the terms of peace offered:

and open unto thee; the gates of the city and its garrisons, and deliver all into their hands:

then it shall be that all the people that is found therein; some having made their escape before the surrender of the city:

shall be tributaries unto thee: pay a yearly tax imposed upon them, as the Moabites sometimes did, and which was paid in lambs and rams with the wool, 2 Kings 3:4

and they shall serve thee; not as slaves, or be in continual bondage and servitude; but upon occasion be called out to any public service, as joining them against their enemies, rebuilding palaces and cities, or repairing walls of cities, and the like; and in general acknowledge their dominion over them, and their own subjection to them, by paying an annual tribute, or sending gifts unto them; thus the Moabites, Syrians, and Edomites, became the servants of David, 2 Samuel 8:2.