Numbers 31:47
Even of the children of Israel’s half, Moses took one portion of fifty, both of man and of beast, and gave them unto the Levites, which kept the charge of the tabernacle of the LORD; as the LORD commanded Moses. Even of the children of Israel’s half, Moses took one portion of fifty, both of man and of beast, and gave them unto the Levites, which kept the charge of the tabernacle of the LORD; as the LORD commanded Moses.
The passage belongs to Israel's first taking of captives, at Midian, when all the males were slain and the women, children, flocks, and herds were seized. Moses rebuked the sparing of the grown women as disobedience to God's command, after which all but the virgins and children were put to death. The virgins and children who were spared and counted in the division of the spoil were to be adopted into the families of the nation rather than enslaved. The arrangement therefore prohibits rather than sanctions the enslavement of prisoners of war, which is the most productive means of making slaves, and it positively bars Israel from becoming a slaveholding nation.
The word soul in the passage is applied without distinction to both human beings and lower animals. In disposing of the captured persons, cattle, donkeys, and sheep taken when Israel defeated the Midianites, one soul out of every five hundred of each was taken. Persons and beeves and asses and sheep were thus reckoned together as souls in making disposition of the spoils.