One difficult halakha that appears in the Torah is the law of eshet yefat to’ar – if a Jewish soldier desires a woman captured in battle, the Torah forbids him to rape her (as is, unfortunately, the case in most armies). Recognizing that in the heat of battle men may want to behave in ways that are not acceptable under normal circumstances, the Torah concedes that the woman can be taken, but she is to be given a month to mourn the loss of her family, and only then will the soldier be given a choice to marry her or to set her free.
Regarding an eshet yefat to’ar the Torah rules ( 21:12) that she should shave her head and “do” her nails. The definition of this term is subject to a disagreement between Rabbi Eliezer and Rabbi Akiva. Rabbi Eliezer rules that she should cut her nails short, while Rabbi Akiva believes that the Torah commands her to allow them to grow.
The Malbim explains the argument as follows. According to Rabbi Eliezer, the purpose of the activities that the Torah requires of the eshet yefat to’ar is a purification process, preparation for joining the Jewish people. We find similar requirements for a mumar (an apostate) who repents, and some say that all converts undergo similar preparations. Just as the levi’im shaved their bodies in preparation for accepting the responsibilities of the Temple service (see 8:7) similarly the eshet yefat to’ar is preparing for her new life.
Rabbi Akiva takes a very different view of the required activities. He sees them as an attempt to remove the beauty and luster of this woman captured in battle, since the Torah prefers that the soldier choose to reject his earlier lust for the foreign woman. Therefore he interprets all of these behaviors in a way that would make the eshet yefat to’ar less attractive.