1) THE PUNISHMENT OF AN INDIVIDUAL IDOLATER COMPARED WITH THE PUNISHMENT OF AN "IR HA'NIDACHAS"
QUESTION: The Gemara quotes a Beraisa which states, "Individuals who serve Avodah Zarah are punished with Sekilah (death by stoning); therefore, their money is saved. Members of an entire community (an Ir ha'Nidachas) who serve Avodah Zarah are punished with Sayif (death by sword); therefore, their money is [also] destroyed."
What is the logical correlation (implied by the word "therefore") between administering the punishment of Sekilah, a more severe punishment, and allowing the executed man's family to keep his possessions, a leniency? Why is the family of a person who was put to death with Sekilah permitted to keep his possessions, while the family of a person who was put to death with Sayif is not permitted to keep his possessions?
ANSWERS:
(a) The VILNA GA'ON (end of SHENOS ELIYAHU to Zera'im) explains that there is a basic difference between the way the Torah relates to an individual who served Avodah Zarah alone and the way the Torah relates to a city of people who served Avodah Zarah collectively. An individual who served Avodah Zarah is treated like any other sinner; he is punished with Sekilah, but his money is not destroyed, because in all cases of Chayavei Misas Beis Din, the possessions of the person who was killed by the court go to his heirs.
In contrast, when an entire city served Avodah Zarah, the Torah views them like Nochrim and treats them as such. As far as the punishment for their sin is concerned, they have forfeited the status of Yisrael. The form of punishment administered to Nochrim who are Chayavei Misas Beis Din is always death by the sword (Sanhedrin 56a), and their possessions are rendered ownerless (Bava Kama 38a). Therefore, when an Ir ha'Nidachas is punished, its inhabitants are killed by the sword and their possessions become ownerless and may be destroyed.
This also explains why an Ir ha'Nidachas may be punished without having been warned with Hasra'ah first, as the Rambam implies. No Hasra'ah is necessary to execute a Nochri who transgressed one of the Seven Mitzvos of Bnei Noach (Sanhedrin 57b).
The MARGOLIYOS HA'YAM (Sanhedrin 111b) provides additional insights into this explanation. He writes in the name of RAV AVRAHAM BINYAMIN KLUGER that there are two types of death sentences issued by Beis Din. The first type is given in order to provide the transgressor with atonement. The second type is given in order to eradicate evil from the world. This is why Nochrim receive the same punishment (Sayif) regardless of which of the Seven Mitzvos of Bnei Noach they transgress, while a Jew sometimes receives a stricter punishment (such as for idol worship) and sometimes a more lenient one. Since the purpose of executing the Nochri for his transgression is to eradicate the evil Nochri from the world, it does not matter which punishment he receives. A Jew, however, who aspires to eternal life in Olam ha'Ba, must receive the punishment which will adequately atone for his sin. Therefore, he may need to receive a harsher punishment.
The same applies in the case of an Ir ha'Nidachas. The people of an Ir ha'Nidachas have no share in Olam ha'Ba (Sanhedrin 111b; see Insights there). Therefore, they receive the same punishment as Nochrim receive, since the purpose of their punishment is not to provide them with atonement but to eradicate the evil from the world. Moreover, the property of such sinful people is also unfit to remain in the world.
In contrast, an individual idol worshipper -- although he committed a grave sin -- still receives atonement from his death because he repents before Beis Din. Although he receives a harsh death as atonement for his sin, his death achieves atonement. Consequently, after his death he is considered to be free of sin and thus his property is permitted to be used.
(b) The MARGOLIYOS HA'YAM cites another explanation. When all of the residents of a city strayed from the proper path, it may be assumed that most were led astray by a few leaders. Every individual in the city is not necessarily absolutely evil to his core. However, the property of all of the residents of the city (including the righteous, according to Rebbi Shimon in Sanhedrin) is burned because it presumably was financial concerns that led these people to reside in such an evil city.
In contrast, an individual who worships idols is intrinsically evil. He conducts himself in a way contrary to the logical and experiential truth of the oneness and omnipotence of Hash-m. Therefore, his body must receive a harsher death. There is no reason to condemn his assets, however, which had nothing to do with his transgression.
This also explains why, in order to punish the idol worshippers of the Ir ha'Nidachas, all of the residents must have lived inside the city. The only reason the people of the city receive a more lenient death is because of the mitigating factor that it was difficult for them to do the right thing in the face of such strong pressure from around them. If the people who persuaded them to serve Avodah Zarah were not from that town, then the sinners deserve the harsher punishment reserved for an individual idol worshipper. (Y. Montrose, Y. Shaw)
2) THE SPECIAL KORBAN OFFERED BY AN "IR HA'NIDACHAS"
QUESTION: Rebbi derives from the verse, "Torah Achas" (Bamidbar 15:16), that an entire city that served Avodah Zarah unintentionally (b'Shogeg) brings the same Korban as an individual who served Avodah Zarah. The Gemara says that without this verse, one would have assumed that they bring different Korbanos, since intentional sinners in an Ir ha'Nidachas receive a different punishment (Sayif, and not Sekilah). The Gemara asks which Korban would they have brought without this verse, as every type of Korban is already taken by a different type of sinner.
Why does the Gemara assert that every type of Korban is already taken? When the Gemara demonstrates how each type of Korban is already reserved for a different type of sinner, it omits a number of Korbanos from its list which are not used already by any other type of sinner, such as a lamb and a ram! (TOSFOS)
Moreover, why does the the Gemara not suggest simply that without the verse of "Torah Achas," the unique Korban which the Ir ha'Nidachas brings is a Korban that is not brought by an individual who commits a sin of Avodah Zarah? Why must their Korban be an entirely unique Korban which is not brought by any sinner? Perhaps their Korban is a Kisbah (she-lamb) or Se'irah (she-goat), the Korban reserved for an individual who commits a sin other than Avodah Zarah. Since an individual who commits the sin of Avodah Zarah brings a different type of Korban, when an entire city sins with Avodah Zarah they should bring the Korban which an individual brings for other sins. (RITVA, RASHBA)
ANSWER: The Rishonim answer that the Gemara assumes that the "new" Korban that an Ir ha'Nidachas might have been required to bring is one that is brought only for a sin (which excludes a lamb and ram). Their Korban cannot be an animal which is never designated to be brought for a sin. On the other hand, the Gemara also assumes that the Korban brought by an Ir ha'Nidachas must be different from any Korban brought for any other sin. If the Ir ha'Nidachas brings a Korban that is already reserved for another sin, their Korban is not unique. Consequently, they cannot bring a unique Korban that is not reserved for any other sin, because no new Korban may be brought for a sin! This is the meaning of the Gemara: the statement that an Ir ha'Nidachas must bring a different type of Korban is a paradox. (See TOSFOS HA'ROSH.)

9b----------------------------------------9b

3) THE APPLICATION OF REBBI CHIYA'S RULING TO THE CASES OF THE MISHNAH
QUESTIONS: The Gemara says that the cases in the Mishnah (2a) are all cases of Nisu'in (in which the woman is an Ervah to the surviving brother through a legitimate marital relationship) and not cases of Onsin (where the woman is an Ervah through rape). Consequently, Rebbi Chiya's statement cannot apply to the Mishnah's case of "Bito" (his daughter). The logic behind this is as follows:
Rebbi Chiya states, "v'Kulan Ani Korei ba'Hen..." -- it is possible to apply the following Halachah to all of the cases in the Mishnah: Two sisters married two brothers, and those two brothers died. One of the sisters is an Ervah to one of the remaining brothers (Levi), but is not an Ervah to the other remaining brother (Yehudah), while the other sister is an Ervah to Yehudah but not to Levi. In that case, each sister may do Yibum or Chalitzah with the brother to whom she is permitted, and there is no problem of "Eshes Zekukaso," since the other woman is not considered Zekukah to the man to whom she is prohibited.
RASHI explains that it is not possible for this statement to be made about the Mishnah's case of "his daughter" whom he bore through marriage. Levi's daughter whom he bore through marriage could not have a sister who was born to his brother, Yehudah (for his wife is not permitted to Yehudah). Rebbi Chiya's statement could apply only to Levi's daughter through rape (whose mother later was raped by Yehudah and bore another daughter).
Rashi here (DH Keivan d'Bito) explains that when the Gemara says that "it is discussing only Nisu'in, and it is not discussing Onsin," the Gemara refers to the Mishnah (2a). The Gemara is not saying that Rebbi Chiya is discussing Nisu'in and not Onsin, but that the Mishnah is discussing Nisu'in and not Onsin.
How are the words of Rashi here to be reconciled with the words of Rashi on the Mishnah (2a, DH v'Em Chamoso)? Rashi there writes that "Bito" in the Mishnah cannot refer to his daughter from his wife, because that would be the same as "Bas Ishto." Rather, Rashi says, it must refer to one's daughter through rape, "Bito me'Anusaso." Accordingly, the Mishnah is discussing cases of Onsin as well as Nisu'in, in contrast to what the Gemara here says! (TOSFOS 2a, DH Bito)
Moreover, the Gemara here attempts to understand why Rebbi did not want to include the case of "Imo Anusas Aviv" (one's mother who was raped by, and not married to, his father) in the list of Arayos in the Mishnah which are exempt from Yibum and which release their Tzaros from Yibum. The Gemara here (and on 10a) gives a number of explanations for why Rebbi did not want to include this case.
If it is true that the Mishnah is discussing only cases of Nisu'in and not Onsin, as the Gemara here asserts according to Rashi, then the Gemara should give a very simple answer: Rebbi did not include the case of "Imo Anusas Aviv" in the Mishnah's list because the Mishnah is not discussing cases of Onsin! The Gemara suggests a number of answers to why the Mishnah does not list "Anusas Aviv," but it does not mention this simple answer. (MAHARSHA)
ANSWER: Many of the Rishonim and Acharonim discuss these questions, but not all of their answers are consistent with the words of Rashi here (see TOSFOS YESHANIM 2a, YASHRESH YAKOV, and others).
The most straightforward approach seems to be as follows. The Gemara here apparently assumes that not all of the cases in the Mishnah are candidates for the Halachah of Rebbi Chiya, "Achosah she'Hi Yevimtah." This is evident from the remarks of Rebbi Yehudah, Abaye, and Rav Safra, who discuss the limitations of this Halachah (that is, to which Arayos in the Mishnah it can be applied and to which it cannot).
The Gemara later (10a), however, evidently has a different approach. The Gemara there says that in order to be included in the Mishnah's list, the case must fit into this category of Rebbi Chiya's Halachah. If it is not a candidate for his Halachah, then it is omitted from the Mishnah's list. The Gemara there apparently revisited its understanding of the statement of Rebbi Chiya.
According to the Gemara's final understanding of Rebbi Chiya -- that the Mishnah lists only cases which fit into this category -- the Mishnah should list only "Bito me'Anusaso" (one's daughter from rape) and not "Bito me'Ishto" (one's daughter from marriage), since "Bito me'Ishto" does not fit into the category of the Halachah of Rebbi Chiya!
Rashi on the Mishnah (2a) therefore explains the Mishnah according to the Gemara's final understanding (10a) of Rebbi Chiya, that applicability to the Halachah of Rebbi Chiya is a criterion for inclusion in the Mishnah. According to this view in the Gemara, why does the Mishnah mention "Bito" (which implies that she is his daughter through his wife as much as it implies that she is his daughter through rape), if the Halachah of Rebbi Chiya cannot apply to the case of "Bito"? Rashi answers this question by saying that "Bito" mentioned in the Mishnah can be understood implicitly as referring only to his daughter from rape (since the Mishnah lists "Bas Ishto" separately from "Bito"). The Mishnah does not need to state explicitly that it means "Bito me'Anusaso" because that is already understood.
Abaye in the Sugya here, however, follows the view which maintains that applicability to Rebbi Chiya's Halachah is not a criterion for inclusion in the Mishnah. That opinion maintains that the case in the Mishnah refers specifically to "Bito me'Ishto" (one's daughter from his wife), the normal case of "Bito." According to that understanding, Rebbi indeed could have said that the Mishnah's list does not include "Imo Anusas Aviv" because it does not list cases of Ones (rape), but he mentioned another reason which is just as valid -- the Mishnah does not list cases about which the Tana'im disagreed.
The Gemara later rejects Abaye's view, as well as the notion that Rebbi did not want to list cases about which the Tana'aim disagreed. At that point, why does the Gemara not give the Maharsha's reason for not including "Imo Anusas Aviv" in the Mishnah -- that the Mishnah does not refer to cases of rape? The answer is that this reasoning is no longer valid; the Gemara at that point maintains that Rebbi Chiya's rule is a criterion for being listed in the Mishnah, and that the Mishnah does refer to "Bito me'Anusaso." (This may be the intention of the RASHBA's answer for Rashi on 2a.)
However, one more point remains to be explained. According to Abaye, why does the Mishnah mention "Bito" if it already mentions "Bas Ishto"? "Bas Ishto" includes "Bito" as well, as Rashi points out in the Mishnah. (For this question, the Rashba (ibid.) offers the somewhat forced answer that "it is the way of the Tana" to list one prohibition twice if it pertains to two different people.)
The ARUCH LA'NER (2a) suggests that the answer is that Abaye maintains that the Ervah of "Bito" is not necessarily included in the category of "Bas Ishto." As mentioned earlier (see Insights to Yevamos 2:1), Rashi maintains that after a man's wife passes away, he no longer is prohibited by an Isur Kares to marry her mother (according to Abaye's understanding of Rebbi Akiva's opinion in Yevamos 76b). In the same vein, Rashi maintains that after a man's wife passes away, he no longer is prohibited to her daughter (since her daughter is prohibited by the same verse that prohibits her mother: "Ervas Ishah u'Vitah Lo Segaleh"). Thus, the Ervah of "Bito" applies to his daughter even after his wife dies, while the Ervah of "Bas Ishto" does not. This is why it is necessary for the Mishnah to mention both cases independently!
(This approach also explains why Rashi here writes that Rebbi Chiya's Halachah cannot apply to "Bito me'Ishto" because the same woman cannot marry the second brother after she was married to the first brother (unless she falls to Yibum, which is not the case here). However, there is another reason Rashi could have mentioned for why Rebbi Chiya's Halachah does not apply to "Bito me'Ishto": When one of the sisters is "Bito me'Ishto," the other sister is "Bas Ishto" and is not permitted to do Yibum with him or with his brother, as Tosfos writes (DH Bito). Why does Rashi not mention this reason? The answer is that according to Rashi, even if one of the sisters is "Bito," the other is not necessarily "Bas Ishto" according to all opinions, since his wife may have died already, in which case her death removed from the sister the Ervah of "Bas Ishto.")
This is true only according to Abaye, who maintains that the Mishnah does not include cases about which the Tana'im disagreed. The Mishnah could not include the case of "Bas Ishto" after the death of the wife, because not all Tana'im consider her to be an Ervah. According to Rav Safra and according to the Gemara's final understanding of Rebbi Chiya's ruling, the Mishnah does include cases about which the Tana'im disagreed. Accordingly, when the Mishnah says "Bas Ishto," it includes even "Bas Ishto" after the death of "Ishto," which is an Ervah only according to some Tana'im (Rebbi Yishmael). Hence, there never will be a case of "Bito" who is not already prohibited due to "Bas Ishto," except for the case of "Bito me'Anusaso." (M. Kornfeld, based on the Aruch la'Ner)