Numbers 31:27
And divide the prey into two parts; between them that took the war upon them, who went out to battle, and between all the congregation: And divide the prey into two parts; between them that took the war upon them, who went out to battle, and between all the congregation:
The command to divide the prey in two belongs to Israel's first taking of captives, in the campaign against Midian when the Israelites killed the males and seized the women, children, flocks and herds. After the return the army was rebuked by Moses for disobeying God's command by sparing the grown women. All but the virgins and children were then put to death. The survivors were reserved for adoption into the families of the nation, not for enslavement as slaves.
In this chapter soul denotes both captured people and animals. The spoil regulations count one soul out of every five hundred.