When thou goest forth to war against thine enemies, and the LORD thy God hath delivered them into thine hands, and thou hast taken them captive,
When thou goest forth to war ... and seest among the captives a beautiful woman (cf. Numbers 31:18). According to the war customs of all ancient nations, a female captive became the slave of the victor, who had the sole and unchallengeable control of right to her person. Moses improved this existing usage by special regulations on the subject. He enacted that, in the event of her master being captivated by her beauty and contemplating a marriage with her, a month should be allowed to elapse, during which her perturbed feelings might be calmed, her mind reconciled to her altered condition, and she might bewail the loss of her parents, now to her the same as dead. A month was the usual period of mourning with the Jews; and the circumstances mentioned here were the signs of grief-the shaving of the head, the (not paring, but literally, doing, i:e.,) allowing the nails to grow uncut, the putting off her gorgeous dress, in which ladies on the eve of being captured arrayed themselves, to be the more attractive to their captors (Ovid, 'Remed. Amor.,'p. 343).
One design of these regulations is thought to have been to prove whether, in the altered appearance of her person, by the emblems or affliction, his attachment would continue undiminished; and they are minutely specified, because, a pagan war-captive, she might, had the matter been left to herself, have followed the mourning rites of her own idolatrous country.
Others view these details as totally unconnected here with a state of mourning, and bearing a different significance. 'The shaving of the head' is reckoned a manifestation of her embracing the Jewish religion, according to a custom prevalent in the East for a Christian to have his head shaved on becoming a proselyte to Mahommedanism. The doing or 'making the nails' is an expression that evidently puzzled our translators: for they have rendered it in two opposite ways - "pare her nails," in the text; 'suffer them to grow,' in the margin (cf. 2 Samuel 19:24). It may probably mean neither, but the tinging them of a red, or, according to some, of a saffron colour, with alkenna, a powder or paste from the pulverized leaves of an odoriferous plant, which, being put on the nails all night, dyes them a bright hue, which lasts for about four weeks, when it is renewed (Hasselquist, 'Travels').
This kind of personal adornment, which is greatly admired in the East, is very ancient, having been seen on the hands and feet of some very old mummies; and if it was commonly practiced in Egypt before the exodus, the Israelites may have borrowed it from that country. The delay was full of humanity and kindness to the female slave, as well as a prudential measure to try the strength of her master's affections. If his love should cool afterward, and he becomes indifferent to her person, he was not to lord it over her, neither to sell her in the slave-market, nor retain her in a subordinate condition in his house, but she was to be free to go where her inclinations led her.