Deuteronomy 20:13-14

And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword:

But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shalt thou take unto thyself; and thou shalt eat the spoil of thine enemies, which the LORD thy God hath given thee.