הלכה על קידושין 42:24

From the roots of the commandment [is that which] they, may their memory be blessed, said (Kiddushin 21b), [it is] because the Torah only permitted the one of beautiful form of the captives in view of the evil impulse. As if Scripture had not permitted her, he would marry her [even though it is] forbidden, due to the power of the evil impulse of the heart of man regarding desire. And so, Scripture shut the door in front of him to make her repulsive in his eyes: It commanded to shave her head so as to destroy the form of her fine hair; and to grow her nails so as to distort the form of her hands; and it permitted her to cry for the first month so as to distort her face and to consume her eyes with her tears. Scripture also commanded that she should sit with him in his house while she is doing all of this in the first month. And it is all to make her disgusting in his eyes, that he come in and go out [from his house] and see her in her distortion. And among the commentators, [some] said (Rabbenu Tam in Tosafot on Kiddushin 22a s.v. shelo) that the permissibility of the first intercourse of the woman of beautiful form is in her being a gentile (immediately). And their words are likely, since her permissibility is because of the power of the evil impulse. But [there are others] among them that said that she is not permissible at all until after all of these acts that we mentioned. And from the simple understanding of the verses, it appears like this. And also in Talmud Yerushalmi Makkot 2:6, they disagreed about this.