Deuteronomy 21:10-14

When you go to war against your enemies, the LORD will help you defeat them so that you will take them captive. If you see a beautiful woman among the captives and are attracted to her, you may take her as your wife. Bring her into your home, where she must shave her head and cut her nails and change the clothes she was wearing when you captured her. After she has lived in your house and cried for her parents for a month, you may marry her. You will be her husband, and she will be your wife. But if you are not pleased with her, you must let her go anywhere she wants. You must not sell her for money or make her a slave, because you have taken away her honor.