QUESTION: The Mishnah discusses a case in which a man died childless and his surviving brother married the Yevamah's sister before he performed Yibum with the Yevamah. The brother's wife (the Yevamah's sister) then died. The Gemara quotes Rav and Rebbi Chanina who rule that the brother may now perform Yibum with the Yevamah.

Why is there any obligation of Yibum in this case? After the woman fell to Yibum, she became exempt from Yibum because the Yavam married her sister and she became his "Achos Ishto" (the sister of his wife). At that moment, she became permitted to marry anyone ("Muteres la'Shuk"). How can the obligation of Yibum return once she became permitted to marry anyone? The principle of "Deracheha Darchei No'am" teaches that the ways of the Torah are ways of pleasantness, and it would not be pleasant for a woman who was exempt from Yibum (and was permitted to remarry) to become obligated to do Yibum (and need to separate from her husband if she already remarried) at a later time (87b; see Insights to Yevamos 30:1).

(a) The RITVA explains that the Yevamah is permitted to marry the brother (the widower of her deceased sister) only when there is a second living brother. Since there is another brother who is permitted to marry her, she never became released from the obligation of Yibum. Since she was permitted to marry the first brother at the moment she fell to Yibum, and since she was never released from the obligation of Yibum due to the presence of another brother, she becomes obligated to do Yibum with the first brother (to whom she became prohibited when he married her sister) when the reason for the prohibition is removed (i.e. at the death of his wife, the Yevamah's sister). (This may also be the opinion of TOSFOS in DH Mesah.)

(b) The RASHBA, however, infers from the Gemara that Rav's ruling applies even when there is no other Yavam. His ruling applies to all of the cases in the Mishnah, even to the last case in which the Yavam died and there clearly is no other Yavam except for the brother who married the Yevamah's sister. The Rashba, therefore, explains Rav's intention as follows.

Rav does not mean that when the brother's wife (the Yevamah's sister) dies, the Yevamah falls to Yibum again. Rather, she indeed is exempt from Yibum because of the principle of "Deracheha Darchei No'am." Rav means that once a man becomes permitted to the wife of his brother ("Eshes Achiv") through the laws of Yibum, he never loses that Heter. This is in accordance with the statement of Rebbi Yochanan (10b) that even after one of the brothers performs Yibum, the other brothers retain the Heter to that woman and are not prohibited to marry her because of the Isur of "Eshes Ach." They are prohibited to marry her only because of the Isur of "Lo Yivneh" (Devarim 25:9).

Similarly, in the case of the Mishnah here, although there was a period of time during which the Yavam was forbidden to the Yevamah (that is, while the Yavam's wife -- the Yevamah's sister -- was alive), the Isur of "Eshes Ach" does not return. When his wife dies, the Yavam has the option of marrying the Yevamah not as a Yevamah but as an ordinary wife. When Rav says, "[Mesah Ishto,] Mutar b'Yevimto," he does not mean that the brother may now do Yibum with the woman, but that he may now marry her as an ordinary wife.

(According to the Rashba, the Gemara apparently refers to a case in which the Yavam did not perform the Chalitzah, which the Mishnah requires, before his wife died. If he already performed Chalitzah, the Yevamah should be forbidden to him because of the prohibition of "Lo Yivneh" which prohibits a person from remarrying his Chalutzah.)

It is unclear whether the Rashba suggests this explanation only according to Rebbi Yochanan (10b) who maintains that the Isur of "Eshes Ach" does not return to the brothers after one of them performs Yibum or Chalitzah (and he means that Rav rules like Rebbi Yochanan). On one hand, his explanation does not seem to conform with the opinion of Reish Lakish who says that the Isur of "Eshes Ach" does return to the brothers once one brother performs Yibum or Chalitzah. Perhaps the Rashba agrees that according to Reish Lakish, in the case of the Mishnah here the Isur of "Eshes Ach" indeed returns when the brother's wife (the Yevamah's sister) dies. On the other hand, perhaps the Rashba gives his explanation even according to Reish Lakish. Reish Lakish says only that the Isur returns when one brother does Yibum or Chalitzah, at which time it becomes clarified retroactively that the woman was always bound specifically to that brother (who performed Yibum or Chalitzah with her) and not to the other brothers. However, when no brother ever fulfilled the Mitzvah (such as in the case of the Mishnah here), perhaps the Heter remains.

Proof for the latter approach may be adduced from the fact that the Gemara needs a verse to teach that the Yavam may divorce the Yevamah and then remarry her. According to the Rashba, a verse is not necessary to teach this, because Rav (and Rebbi Yochanan) maintain that it is obvious that the Yavam may remarry the Yevamah; logic dictates that the Isur of "Eshes Ach" cannot return once it has been removed. Rather, the Gemara understands that one might have thought that after Yibum is performed and the Mitzvah fulfilled, the Heter is revoked and the Yevamah becomes prohibited to the brother again. Therefore, the verse must teach that the Heter remains (for the brother who performed Yibum according to Reish Lakish, and for all of the brothers according to Rebbi Yochanan; see also Insights to Yevamos 10:1).

The Gemara discusses the principle, "Kol ha'Oleh l'Yibum, Oleh l'Chalitzah" -- anyone who may perform Yibum may perform Chalitzah, and anyone who may not perform Yibum may not perform Chalitzah. The Gemara applies this principle to a Yevamah within three months after the death of her husband. Since she may not do Yibum (because of the requirement that she wait three months to verify that she is not pregnant), she also may not do Chalitzah.

RASHI explains that the Gemara does not mean that if the Yevamah does Chalitzah within three months after the death of her husband, the Chalitzah does not take effect. Rather, the Gemara means that since it is possible to wait until she becomes fit for Yibum, l'Chatchilah she must wait and perform Chalitzah only after she becomes fit for Yibum. This application of the principle of "Kol ha'Oleh l'Yibum..." differs from the way the Gemara has applied it until now. The Gemara discusses this principle with regard to several types of cases. These different types of cases can be grouped into six categories:

(a) ISUR YIBUM MI'SAFEK. The Gemara here discusses whether the principle applies in a case in which Yibum cannot be done because of a doubt, where details about the specific case are missing (such as within the first three months after the death of the husband, when there is a doubt whether or not she is pregnant and exempt from Yibum). RASHI and TOSFOS explain that it is obvious that if her obligation to do Yibum or Chalitzah cannot be clarified at a later time, she certainly may perform Chalitzah out of doubt even though she may not do Yibum (since she might not be obligated).

The Gemara concludes that even when it is possible to clarify the doubt at a later time, it still is not necessary to wait until that time to do Chalitzah. The Yevamah may do Chalitzah even l'Chatchilah during the time that her obligation is subject to doubt and she is not fit for Yibum. (The reason for this is that she might indeed be fit for Yibum and Chalitzah at this moment.)

(b) ISUR YIBUM MID'RABANAN. In a case in which the Chachamim prohibited Yibum, the law is that if the Chachamim's prohibition will not be removed at a later date, certainly she may perform Chalitzah immediately because, mid'Oraisa, the woman has an obligation to do Yibum and may not marry until she releases herself from that obligation. On the other hand, if the Chachamim's prohibition will be removed at a later date (such as when she has fulfilled their enactment to wait three months after her husband died before she does Yibum), l'Chatchilah she should not do Chalitzah until after the Chachamim's prohibition of Yibum is removed and she becomes fit to do Yibum.

(c) ISUR NIDAH. The third case is that of a woman who falls to Yibum while she is a Nidah. In such a case, Yibum is forbidden mid'Oraisa because she is a Nidah. The TOSFOS HA'ROSH (2a) suggests that even if Yibum cannot take effect with a Nidah, nevertheless Chalitzah may be done with her while she is a Nidah. The reason for this is that the Isur of Nidah is expected to depart after the passage of a given amount of time. The bond of Zikah obligates her to do Yibum since she is expected to be fit to do Yibum later. As a result, she may do Chalitzah even now, during the time that she is a Nidah.

(Tosfos and the Rosh (2a) have a doubt about whether the act of Yibum is valid when a man performs Yibum while he transgresses the Isur d'Oraisa of Nidah. If the Yibum is valid b'Di'eved, a Yevamah who is a Nidah is considered fit to be "Oleh l'Yibum" and she does not fall into the category of "Kol she'Eino Oleh l'Yibum...," even though performing Yibum with her l'Chatchilah is Asur mid'Oraisa.)

(d) CHAYAVEI LAVIM. The Gemara earlier (20a) states that when the Yavam is forbidden from doing Yibum with the Yevamah because of an Isur Lo Ta'aseh which prohibits her to him, he still may do Chalitzah even though an act of Yibum would not be valid even b'Di'eved. The Chalitzah is valid in this case because the Torah adds the word, "Yevimto" (Devarim 25:7), which includes Chayavei Lavim in the obligation of Chalitzah while it exempts them from Yibum. The Rishonim there point out that the Gemara concludes that the Mitzvas Aseh of Yibum overrides the Lo Ta'aseh of an Isur Lav, and thus, mid'Oraisa, Chayavei Lavim are fit to do Yibum. However, the verse quoted there is used to teach a different exception to the principle of "Kol she'Eino Oleh l'Yibum" -- the case of a woman who cannot do Yibum because she is forbidden to the Yavam with an Isur Aseh (such as a Be'ulah to a Kohen Gadol). The woman still has an obligation to do Chalitzah because of this verse, even though she is not fit for Yibum.

RASHI (3a, DH Havah Amina) apparently disregards this exception to the rule of "Kol she'Eino Oleh l'Yibum...." Rashi writes that the Halachah of "Choletzes v'Lo Misyabemes" (she must do Chalitzah and may not do Yibum) applies only when the woman is forbidden to the Yavam due to a Safek Isur. He mentions no other case in which "Choletzes v'Lo Misyabemes" applies. It is understandable why Rashi omits the second category mentioned above, a case in which the Chachamim prohibited Yibum, as Rashi refers only to situations of "Choletzes v'Lo Misyabemes" which are mid'Oraisa and the only such case is a Safek Isur. REBBI AKIVA EIGER (in Gilyon ha'Shas) questions why Rashi ignores the cases of women who are forbidden to their Yavam because of a Chiyuv Aseh. In such cases, the Mitzvah of Yibum does not override the Isur and yet she is still required to do Chalitzah because of the verse, "Yevimto."

Perhaps the answer is that Rashi follows his own opinion as expressed elsewhere (Yevamos 9a, Sanhedrin 53a). Rashi maintains that when an Isur Lav prohibits a woman to the Yavam, she is prohibited mid'Oraisa from doing Yibum. That is, the principle of "Aseh Docheh Lo Ta'aseh" does not apply to a case of Yibum. According to Rashi, if the Yavam transgresses the Chiyuv Lav or Chiyuv Aseh and has relations with the Yevamah, b'Di'eved the Yibum takes effect and he is Koneh her (see Insights to Yevamos 20:4). Although he transgressed an Isur, the Yibum takes effect (as Tosfos says with regard to Yibum with a Nidah, as mentioned above). Hence, she is considered "Oleh l'Yibum," and that is why she does Chalitzah. This explains why Rashi does not list the cases of Chiyuv Lav and Chiyuv Aseh as cases of "Choletzes v'Lo Misyabemes"; Rashi refers only to cases where Yibum may not be done and where, b'Di'eved, if Yibum was done it does not take effect.

(e) ME'UBERES. Rava (36a) states that if Yibum may not be done with a pregnant Yevamah, Chalitzah also may not be done with her because she is not "Oleh l'Yibum." RAV ELCHANAN WASSERMAN (Kovetz He'oros 38:2) points out that this is not the classic case of "Kol she'Eino Oleh l'Yibum, Eino Oleh l'Chalitzah," because after the baby is found to be a stillborn certainly Yibum and Chalitzah may be done. Since the obligation of Yibum exists at that time, obviously Zikah of Yibum exists retroactively from the moment the Yevamah fell to Yibum when her husband died. This is also evident from the fact that the Yavam is not obligated to bring a Korban Chatas if he had relations with the Yevamah before her baby was found to be a stillborn (see Insights to Yevamos 35:2). Nevertheless, since he cannot actually have relations with her now, she is considered "Eino Oleh l'Yibum." This is why Rashi explains the principle of "Kol she'Eino Oleh" slightly differently in that Sugya.

What is the difference between this case and the case of Nidah, in which Chalitzah may be done now since Yibum will be permitted later? The TOSFOS HA'ROSH asks this question and answers that a Nidah is fully expected to become permitted later, while, in this case, there is no way of knowing whether the woman will be permitted to do Yibum later or not (it depends on whether the baby lives or dies). Therefore, it is a case of "Eino Oleh l'Yibum."

(f) CHAYAVEI KERISUS. When a woman cannot do Yibum because she is forbidden to the Yavam with an Isur Kares (for example, she is "Achos Ishto," the sister of his wife), the Torah exempts her from Chalitzah as well as Yibum: since she has no "Zikah for Yibum" she has no "Zikah for Chalitzah" (20a). Similarly, after the brother does Yibum with one of the Yevamos (44a), he may not do Yibum with her Tzarah because of the rule that "Bayis Echad Hu Boneh" -- one may build only one "house" for his brother (by doing Yibum with one of his wives) and not two. Consequently, one cannot do Chalitzah with the second wife because there is no longer any Zikah of Yibum to that wife. (This is the classic case of "Kol she'Eino Oleh l'Yibum, Eino Oleh l'Chalitzah.")