Numbers 31:14

And Moses was wroth with the officers of the host, with the captains over thousands, and captains over hundreds, which came from the battle.

Moses was wroth. The displeasure of the great leader, though it appears the ebullition of a fierce and sanguinary temper, arose in reality from a pious and enlightened regard to the best interests of Israel. No order had been given for the slaughter of the women, and in ancient war they were commonly reserved for slaves. By their antecedent conduct, however, the Midianitish women had forfeited all claims to mild or merciful treatment; and the sacred character, the avowed object of the war (Numbers 31:2), made their slaughter necessary without any special order. But why "kill every male among the little ones"? It was designed to be a war of extermination, such as God Himself had ordered against the people of Canaan, whom the Midianites equalled in the enormity of their wickedness. In regard to the women, all of mature age, having been engaged in the work of seduction, were to share the same merciless fate as the men; but the younger girls, being guiltless of that crime, were to be spared, and treated according to the humane rules prescribed for the disposal of female captives, whom their masters, it is presupposed, would marry (see the notes at Deuteronomy 21:10).