Deuteronomy 20:12-14

12And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it: 13And when the LORD thy God hath delivered it into thy hands, thou shalt smite every male of it with the edge of the sword: 14But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil of it, shalt thou take to thyself; and thou shalt eat the spoil of thy enemies, which the LORD thy God hath given thee.1