Deuteronomy 20:13 in the King James Version
And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword:
Context
12 If it will make no peace with you, but will make war against you, then you shall besiege it.
13 When the LORD your God delivers it into your hand, you shall strike every male of it with the edge of the sword;
14 but the women, the little ones, the livestock, and all that is in the city, even all its plunder, you shall take for plunder for yourself. You may use the plunder of your enemies, which the LORD your God has given you.