Deuteronomy 21:10-13

10“When you go out to battle against your enemies, and the Lord your God hands them over to you and you lead them away captive,

11and you see a beautiful woman among the captives, and desire her and would take her as your wife,

12then you shall bring her [home] to your house, and she shall shave her head and trim her nails [in preparation for mourning].

13She shall take off the clothes of her captivity and remain in your house, and weep (mourn) for her father and her mother a full month. After that you may go in to her and be her husband and she shall be your wife.