Deuteronomy 21:11 (KJV)

So shalt thou put away the guilt of innocent blood from among you, when thou shalt do that which is right in the sight of the Lord.

When thou goest forth to war against thine enemies, and the Lord thy God hath delivered them into thine hands, and thou hast taken them captive,

And seest among the captives a beautiful woman, and hast a desire unto her, that thou wouldest have her to thy wife;

Then thou shalt bring her home to thine house; and she shall shave her head, and pare her nails;

And she shall put the raiment of her captivity from off her, and shall remain in thine house, and bewail her father and her mother a full month: and after that thou shalt go in unto her, and be her husband, and she shall be thy wife.