QUESTION: The Mishnah (43b) states that when a man dies childless and leaves behind two wives, his brother does Yibum or Chalitzah with one of the wives and thereby exempts the other wife from her obligation of Yibum. The Gemara asks why the brother is not required to do Chalitzah with the second woman after he does Yibum with the first. The Gemara answers that since he may not do Yibum with the second woman ("Bayis Echad Hu Boneh" -- "one may build only one house, and not two," as derived from Devarim 25:9), he also may not do Chalitzah. The principle of "Kol she'Ein Oleh l'Yibum, Ein Oleh l'Chalitzah" teaches that when Yibum may not be done, Chalitzah also may not be done.

The Gemara adds that "in addition, people should not say that half of the brother's house is being built, and half is doing Chalitzah." The Gemara asks what difference would it make if people say that, and it answers that when people see the Yavam do Yibum with the first woman and Chalitzah with the second, they might think that one is permitted to do the two procedures in any order, and they will permit doing Chalitzah first and then Yibum (which is prohibited because "Keivan she'Lo Banah, Shuv Lo Yivneh").

Why does the Gemara add this second reason? The first reason explains why the Torah does not require that Chalitzah be done with the second woman. The Derashah of "Bayis Echad Hu Boneh" and the principle of "Kol she'Ein Oleh l'Yibum" are mid'Oraisa. Hence, mid'Oraisa the brother does not need to do Chalitzah with the second woman. Why does the Gemara add a second reason which is only mid'Rabanan, a Gezeirah to prevent people from confusing the order and permitting Yibum after Chalitzah? If Chalitzah is not needed mid'Oraisa, there obviously is no need to explain why the Rabanan enacted that it not be done! Moreover, if there indeed is some reason to obligate the brother mid'Oraisa to do Chalitzah with the second woman, how can the Rabanan prohibit Chalitzah and permit a Yevamah to remarry without releasing herself from the obligation of Yibum?

(a) TOSFOS' text of the Gemara omits the second reason of the Gemara and includes only the reason why Chalitzah is not done mid'Oraisa. The Rishonim, however, cite the Girsa of the RIF and RABEINU CHANANEL whose text does include the second reason.

(b) The RAMBAN and RASHBA explain the Gemara as follows. Although the Torah gives a reason for why the brother should not do Chalitzah with the second woman, the Rabanan are entitled to enact a decree that he do Chalitzah with her so that people (who are not aware that her Tzarah did Yibum) not mistakenly assume that a Yevamah may remarry without being released from her obligation of Yibum. The Gemara answers that the Rabanan carefully weighed the implications of such an enactment and they reasoned that if the second woman would be required (mid'Rabanan) to do Chalitzah, an even bigger problem might occur -- people might mistakenly assume that the brother may do Chalitzah first and then Yibum. Therefore, they did not enact that Chalitzah be done with the second woman.

(c) The RITVA explains that the Gemara does not merely give a reason for why there is no obligation to do Chalitzah with the second woman after Yibum is done with the first. Rather, the Gemara teaches that the brother is forbidden to do Chalitzah with the second woman. When the principle of "Kol she'Ein Oleh l'Yibum, Ein Oleh l'Chalitzah" dictates that there is no obligation to do Chalitzah with the second woman, it must mean that Chalitzah is also forbidden. It is logical that wherever the Torah does not obligate one to do Chalitzah, it forbids Chalitzah, because the act of Chalitzah involves excessive disgrace to the parties involved. The Gemara then says that even if this consideration is not reason enough to forbid Chalitzah mid'Oraisa, it still should be Asur mid'Rabanan because of the concern that people might permit the brother to do Chalitzah first and then Yibum.