Deuteronomy 20

10. 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.

12. And if he will make no peace. The permission here given seems to confer too great a license; for, since heathen writers ² command even the conquered to be spared, and enjoin that those should be admitted to mercy who lay down their arms, and cast themselves on the good faith of the General, although the battering-ram may have actually made a breach in the wall, how does God, the Father of mercies, give His sanction to indiscriminate bloodshed? It has already been stated, that more was conceded to the Jews on account of their hardness of heart, than was justly lawful for them. Unquestionably, by the law of charity, even armed men should be spared, if, casting away the sword, they crave for mercy; at any rate it was not lawful to kill any but those who were taken in arms, and sword in hand. This permission, therefore, to slaughter, which is extended to all the males, is far distant from perfection. ³ But, although in their ferocity the Jews would have hardly suffered the perfection of equity to be prescribed to them, still God would at least restrain their excessive violence from proceeding to the extremity of cruelty. The question is as to cities taken by force, where it sometimes happens that there is no distinction of sex or age regarded; this inhumanity is here mitigated, since they might not kill either women or children.

15. Thus shalt thou do unto all the cities. An exception is introduced, that the Jews should not apply the common laws of war to the Canaanitish nations, with respect to whose extermination the sentence had passed. ⁴ For God had not only armed the Jews to carry on war with them, but had appointed them to be the ministers and executioners of His vengeance. We have elsewhere explained that there were just causes why He would have their race and memory radically destroyed; especially since He had borne with them for four hundred years, whilst in their wicked obstinacy they had not ceased to grow worse and worse, from whence their desperate impiety was manifest. What had been said before is here, however, repeated, i.e., that since that land was consecrated to God's service, its inhabitants were to be exterminated, who could do nothing but contaminate it; and therefore this would be profitable for the Israelites, lest by their wiles they should be attracted to false superstitions.