When thou goest forth to war. He now teaches that, even in lawful wars, cruelty is to be repressed, and bloodshed to be abstained from as much as possible. He therefore commands that, when they shall have come to take a city, they should first of all exhort its inhabitants to obtain peace by capitulating; and if they should do so, to keep them alive, and to be content with imposing a tribute on them. This principle of equity was naturally implanted in all nations; hence heralds took their rise, [1] nor did they commence a just war without a solemn proclamation. Besides, inasmuch as the word hostis (an enemy) formerly signified a foreigner (peregrinum,) the Romans mitigated by its mildness the sadness of the reality. On this ground they deemed that faith was to be kept with an enemy; and that sentiment of Cicero is worthy of praise, "that wars must not be undertaken except that we may live in unmolested peace." But if God would have his people mindful of humanity in the very midst of the din of arms, we may hence infer how greatly displeasing to Him is human bloodshed. Even those whom He has armed with his authority, He would still have disposed to clemency, and He represses their ardor, lest they should stain with blood the swords given them by His permission. How, then, shall it be lawful for a private person to assume the sword for the purpose of killing his brother? We now understand the object of the instructions here given, and how appropriately they are connected with the Sixth Commandment.

Footnotes

1 - "Feciales." -- Lat. "Les herauts d'armes." -- Fr. "The Romans never carried on any war without solemnly proclaiming it. This was done by a set of priests called Feciales. When the Romans thought themselves injured by any nation, they sent one or more of these Feciales to demand redress, (ad res repetundas,) Liv. 4:30, 38:45. Varro, L.L. 4:15. Dionys. 2:72; and, if it was not immediately given, thirty-three days were granted to consider the matter, after which war might be justly declared. Then the. Feciaks again went to their confines, and having thrown a bloody spear into them, formally declared war against that nation, Liv. 1:32." -- Adam's Romans Antiq. The references in the two following sentences are to Cicero, de Off. 1:12, and 11, and 13.

Directions intended to prevent wanton destruction of life and property in sieges.

Proclaim peace unto it - Interpreters are greatly divided concerning the objects of this law. The text, taken in connection with the context, (see Deuteronomy 20:15-18), appears to state that this proclamation or offer of peace to a city is only to be understood of those cities which were situated beyond the limits of the seven anathematized nations, because these latter are commanded to be totally destroyed. Nothing can be clearer than this from the bare letter of the text, unless some of the words, taken separately, can be shown to have a different meaning. For the common interpretation, the following reasons are given.
God, who knows all things, saw that they were incurable in their idolatry; that the cup of their iniquity was full; and as their Creator, Sovereign, and Judge, he determined to destroy them from off the face of the earth, "lest they should teach the Israelites to do after all their abominations," Deuteronomy 20:18. After all, many plausible arguments have been brought to prove that even these seven Canaanitish nations might be received into mercy, provided they,
1. Renounced their idolatry;
2. Became subject to the Jews; and,
3. Paid annual tribute: and that it was only in case these terms were rejected, that they were not to leave alive in such a city any thing that breathed, Deuteronomy 20:16.

When thou comest nigh unto a city to fight against it,.... This is to be understood of an arbitrary war, as Jarchi observes; which they engaged in of themselves, or were provoked to by their enemies; which was their own choice, and according to their own will and pleasure; and their conduct towards their enemies in it was different from that in a war with the seven nations, commanded by the Lord, and distinguished from it, Deuteronomy 20:15.
then proclaim peace unto it; that is, offer them terms of peace; which were, that the inhabitants of it should renounce idolatry, and become their tributaries and servants.

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.

When thou comest nigh unto a city to fight against it, then proclaim peace unto it--An important principle is here introduced into the war law of Israel regarding the people they fought against and the cities they besieged. With "the cities of those people which God doth give thee" in Canaan, it was to be a war of utter extermination (Deuteronomy 20:17-18). But when on a just occasion, they went against other nations, they were first to make a proclamation of peace, which if allowed by a surrender, the people would become dependent [Deuteronomy 20:11], and in the relation of tributaries the conquered nations would receive the highest blessings from alliance with the chosen people; they would be brought to the knowledge of Israel's God and of Israel's worship, as well as a participation of Israel's privileges. But if the besieged city refused to capitulate and be taken, a universal massacre was to be made of the males while the women and children were to be preserved and kindly treated (Deuteronomy 20:13-14). By this means a provision was made for a friendly and useful connection being established between the captors and the captives; and Israel, even through her conquests, would prove a blessing to the nations.

Instructions Concerning Sieges. - Deuteronomy 20:10, Deuteronomy 20:11. On advancing against a town to attack it, they were "to call to it for peace," i.e., to summon it to make a peaceable surrender and submission (cf. Judges 21:13). "If it answered peace," i.e., returned an answer conducing to peace, and "opened" (sc., its gates), the whole of its inhabitants were to become tributary to Israel, and serve it; consequently even those who were armed were not to be put to death, for Israel was not to shed blood unnecessarily. מס does not mean feudal service, but a feudal slave (see at Exodus 1:11).