13 Then Moses and Eleazar the priest and the chiefs of the people went out to them before they had come into the tent-circle. 14 And Moses was angry with the chiefs of the army, the captains of thousands and the captains of hundreds who had come back from the war. 15 And Moses said to them, Why have you kept all the women safe? 16 It was these who, moved by Balaam, were the cause of Israel's sin against the Lord in the question of Peor, because of which disease came on the people of the Lord. 17 So now put every male child to death, and every woman who has had sex relations with a man. 18 But all the female children who have had no sex relations with men, you may keep for yourselves.
Matthew Henry's Commentary on Numbers 31:13-18
Commentary on Numbers 31:13-18
(Read Numbers 31:13-18)
The sword of war should spare women and children; but the sword of justice should know no distinction, but that of guilty or not guilty. This war was the execution of a righteous sentence upon a guilty nation, in which the women were the worst criminals. The female children were spared, who, being brought up among the Israelites, would not tempt them to idolatry. The whole history shows the hatefulness of sin, and the guilt of tempting others; it teaches us to avoid all occasions of evil, and to give no quarter to inward lusts. The women and children were not kept for sinful purposes, but for slaves, a custom every where practised in former times, as to captives. In the course of providence, when famine and plagues visit a nation for sin, children suffer in the common calamity. In this case parents are punished in their children; and for children dying before actual sin, full provision is made as to their eternal happiness, by the mercy of God in Christ.