Numbers 31:17-18
kill ... boy ... kill ........... man <02145 02026> [kill every male.]
The sword of war should spare women and children, as incapable of resisting; but the sword of justice knows no distinction, except that of guilty or not guilty, or more or less guilty. This was the execution of a righteous sentence upon a guilty nation, in which the women were the greatest criminals; and it may safely be said, that their lives were forfeited by their personal transgressions. With respect to the execution of the male infants, who cannot be supposed to have been guilty, God, the author and supporter of life, who has a right to dispose of it when and how he thinks proper, commanded it; and "shall not the Judge of all the earth do right?"
boy ............. man <02145> [him. Heb. a male.]
yours <02421> [keep alive for yourselves.]
It has been groundlessly asserted, that Moses here authorised the Israelites to make concubines of the whole number of female children; and an insidious objection against his writings has been grounded upon this monstrous supposition. But the whole tenor of the law, and especially a statute recorded in De 21:10-14, proves most decisively to the contrary. They were merely permitted to possess them as female slaves, educating them in their families, and employing them as domestics; for the laws concerning fornication, concubinage, and marriage, were in full force, and prohibited an Israelite even from marrying a captive, without delays and previous formalities; and if he afterwards divorced her, he was to set here at liberty, "because he had humbled her."
Numbers 32:16
This proposal was very equitable, and it was honestly made and faithfully executed; though it did not imply that all men capable of bearing arms should go, and so leave their families and possessions defenceless, but only a sufficient detachment of them. Among the inhabitants of the land were the Ammonites, Moabites, Idumeans, and the remains of the Midianites and Amorites; and as it was impossible for the women and children to keep the defenced cities, when placed in them, many of the men of war must of course stay behind. In the last census (ch. 26), the tribe of Reuben consisted of 43,730 men; the tribe of Gad 40,500; and the tribe of Manasseh 52,700; the half of which is 26,350; which together amount to 110,580. Now from Jos 4:13, we learn, that of these tribes only 40,000 armed men passed over Jordan to assist their brethren: consequently 70,580 men were left behind for the defence of the women, the children, and the flocks: which was amply sufficient for this purpose.