Deuteronomy 21:10-17

¹⁰When thou goest out to war against thy enemies, and the Lord thy God doth deliver them into thy hand, and thou takest them captive;

¹¹And thou seest among the captives a woman of fair countenance, and hast a desire for her, and wouldst take her unto thee to wife;

¹²Then thou shalt bring her into thy house, and she shall shave her head, and pare her nails,

¹³And take off from her the dress of her captivity, and dwell in thy house, and mourn for her father and mother a month of days; and afterward thou mayest go to her and marry her, and she shall be thy wife.

¹⁴But if it be that thou hast no pleasure in her, then thou mayest send her away by herself: thou shalt in no wise sell her for money, nor make merchandise of her, for thou hast afflicted her.

¹⁵If a man have two wives, the one beloved and the other hated, and they have borne sons, the beloved one and the hated one, and the firstborn son belong to the hated;

¹⁶Then in the day that he maketh his sons to inherit what he hath, he shall not make the son of the beloved to be (as) the firstborn over the head (face) of the son of the hated, the (actual) firstborn.

¹⁷For he shall distribute to the firstborn the son of the hated by giving him two parts of all his possession; for he is the beginning of his strength, and to him pertaineth the birthright.