Deuteronomy 21:10-17

¹⁰When you go to war with your enemies and the Lord your God hands them over to you in defeat, and you capture them,

¹¹you may see that one of them is a beautiful woman who you like and want to marry.

¹²Take her home and have her shave her head, cut her nails,

¹³and get rid of the clothes she was wearing when she was captured. After she has lived in your home and has finished her month of mourning for her father and mother, you may sleep with her and marry her, and she shall be your wife.

¹⁴However, if you are not happy with her, you must let her leave and go wherever she wants. You are not allowed to sell her for money or treat her like a slave, because you have brought shame on her.

¹⁵If a man has two wives, one he loves and one he doesn't, and both have sons by him, but the firstborn son is from the wife he doesn't love,

¹⁶when the time comes for the man to decide what each son will inherit from him, he must not prefer the son of wife he loves and treat him as the firstborn instead of the son of the wife he doesn't love.

¹⁷No. He is to recognize the firstborn, the son of the wife he doesn't love through the usual custom of giving him a double portion of all that he owns. The firstborn son is the firstfruits of his father's strength, and so the rights of the firstborn are his.