Nedarim Chart #3

(2) No Neder can obligate a person to actively do something, as the Ran explains (8a, DH v'ha'Lo). (Even if Nidrei Mitzvah, just like Nidrei Hekdesh, *can* obligate a person to actively do something, as the RITVA and those who disagree with the Ran there write, they certainly cannot obligate a person to *transgress* a Mitzvah.)

(3) See previous footnote. However, the Ba'al ha'Me'or (Shevuos, end of Perek 3), says that both a "Neder" and a Shevu'ah take effect to obligate him to actively fulfill a Mitzvah. The Ba'al ha'Me'or is learning the Gemara on 8a, "Neder Gadol Nadar," to be referring literally to a Neder, like the RITVA there, because Nidrei *Mitzvah* can obligate a person to actively do something; see previous footnote.

(4) Ba'al ha'Me'or in Shevuos, end of Perek 3, at the very end of his comments. This is also the opinion of the TOSFOS (in Shevuos 20b, DH d'Chi) and the Rashba (Nedarim 18a), before he changed his mind. Their reasoning is that "Ein Isur Chal Al Isur," an Isur cannot take effect on another Isur, applies even for an Isur Cheftza taking effect on an Isur Torah (such as the Isur of eating on Yom Kipur). The Rashba, though, raises the possibility that perhaps an Isur Neder does take effect on *another Isur Neder* (to make him obligated twice). He learns this from the Gezeiras ha'Kasuv of "Nazir l'Hazir," which, he maintains, teaches that a Neder can take effect on top of *any* Isur that comes as a result of a person, such as Nezirus or Neder. (This is diametrically opposed to the opinion of the Ran, see footnote 5 below, which the Rashba eventually adopted as well, that a Neder *cannot* take effect on another Neder, but it *does* take effect on an any other Isur Torah.)

(5) Rashi in Shevuos (20b, DH Hachi Garsinan), the Ramban in Milchamos (Shevuos, end of Perek 3) and the Ran (Nedarim 18a). This is also the conclusion of the Rashba (as cited from his TESHUVOS (1:615) and from the SHITAH MEKUBETZES in the "Hashmatos" of the Rashba, Nedarim 18a). Their reasoning is that all Isurim of the Torah are Isurei Gavra, and a Neder -- which is an Isur Cheftza -- can take effect on them, just like it can take effect to *override* a Mitzvah for this reason. Hence, "Ein Isur Chal Al Isur" is not applicable. However, if an object is already Asur because of a Neder, a second Neder cannot take effect on it, since the object is already Asur with an Isur Cheftza. This is why a Neder cannot take effect on a pre- existing Neder (except for an oath of Nezirus, like the Mishnah on 17a says). The MILCHAMOS (ibid.), though, maintains that a Neder can even take effect on an object that was already prohibited through another *Neder*.
Rebbi Akiva Eiger, in his notes on the Shulchan Aruch (YD 238), suggests that all of this applies only to an Isur Torah which has nothing to do with an Isur Cheftza, such as one who makes a Neder prohibiting himself from food on Yom Kipur (where the Isur Torah not to eat is solely an Isur Gavra), which is the case that Rashi discusses in Shevuos (loc. cit.). However, if one makes a Neder to prohibit Neveilos and Treifos, then everyone will agree that the Neder does not take effect, because the *Cheftza* is already prohibited by the Torah. A very strong proof for Rebbi Akiva Eiger's words can be adduced from the Gemara in Kerisus that says that an Isur Hekdesh cannot take effect on an Isur Chelev, except through the mechanics of "Isur Kolel" or "Isur Mosif." We know that an Isur Hekdesh is a type of Isur Neder (i.e. it is a Davar ha'Nadur and an Isur Cheftza, since an object Hekdesh may be used for Hatfasah for Nidrei Isur). If so, why does it not take effect on an Isur Chelev (as the Avnei Milu'im indeed asks in Teshuvah #12)? According to Rebbi Akiva Eiger, it is clear -- Chelev is an Isur *Cheftza* and thus even a Neder cannot take effect on it.
However, Rav Yisrael Ze'ev Gustman zt'l points out (in Kuntresei Shiurim, Nedarim #9) that according to this, the Isur of Neveilah should take effect if an animal dies on Yom Kipur, since the Isur of Neveilah has an added element of an Isur Cheftza just like a Neder. Yet the Gemara in Kerisus says that it does not take effect on top of another Isur without "Kolel" or "Mosif!" (Rav Gustman, Zatzal, leaves this question on Rebbi Akiva Eiger unanswered.) Perhaps we might suggest that a prohibited object is not considered an Isur Cheftza unless it was Asur from its very inception, such as Chelev, Gid, and non-kosher animals. An animal that became a Neveilah, though, was not a Neveilah until it died (M. Kornfeld).

(6) The opinion of Rebbi Yehudah ben Beseirah, that a Shevu'ah does not have to have the option of being made through both "Lav v'Hen," is recorded in the Mishnah in Shevuos (27a, and Rashi there), and Rashi appears to have understood that to mean that an Isur Shevu'ah can even take effect on an object that is already Asur mid'Oraisa (see Tosfos there). Tosfos in Shevuos (20b, DH d'Chi) also writes that a Shevu'ah may take effect on an Isur Torah according to Rebbi Yehudah ben Beseirah.

(7) Tosfos in Shevuos (27a, DH l'Kayem), in the name of the RIVA. His reasoning is that even Rebbi Yehudah ben Beseirah agrees that "Ein Isur Chal Al Isur" and therefore no special verse is needed to teach that a Shevu'ah cannot take effect on what is prohibited by the Torah. In Yevamos (33b) it is clear that even though "Ein Isur Chal Al Isur" applies with regard to Malkus, the second Isur *does* take effect insofar as creating an additional Isur, such that the person who transgresses will be transgressing an additional Isur. (The practical ramification of this is that one who transgresses the double Isur "will be buried among Resha'im Gemurim," the truly evil.) If so, a Shevu'ah too should take effect on an Isur Torah with regard to creating an additional Isur (but not with regard to Malkus), as the Ketzos ha'Choshen indeed writes (73:5). The Ketzos' conclusion is also supported by the Rambam (Hilchos Shevu'os 4:10 and 6:14) who implies that a Shevu'ah takes effect on another Shevu'ah insofar as creating an additional Isur. (This is in contrast to what the Ketzos himself writes in Teshuvos Avnei Milu'im #12; see Insights; see also the notes of Rav Aharon Yaffen zt'l on the Ritva, Perek 1 footnote 171, and in his appendix 10:1, for a more lengthy discussion of this matter.)
(Referring to the words of the Rishonim, it would seem that this question depends on the Machlokes between the Ramban and Ba'al ha'Me'or whether a Shevu'ah to fulfill a Mitzvah takes effect for Malkus or not (see Chart, 2b:A). According to the Ramban who says that it does *not* take effect at all, a Shevu'ah cannot take effect on something for which the person is already "Mushba" even where "Ein Isur Chal Al Isur" is not applicable (such as to fulfill a Mitzvah through Kum v'Aseh). If so, the same applies when one makes a Shevu'ah to observe a Mitzvah of Shev v'Al Ta'aseh -- the Shevu'ah does not take effect even with regard to adding an extra degree of Isur. According to the Ba'al ha'Me'or, on the other hand, a Shevu'ah *would* take effect on another Shevu'ah if not for the principle of "Ein Isur Chal Al Isur." Therefore, the second Shevu'ah *does* take effect with regard to adding an extra degree of Isur, like the Gemara in Yevamos says regarding every case of a second Isur taking effect on a previous Isur. However, the Avnei Milu'im (ibid.) proposes that according to those who hold like the Ba'al ha'Me'or, a Shevu'ah is entirely null and void when it cannot create a Chiyuv Malkus, unlike an Isur Torah.)

(8) The Rabanan's opinion also appears in the Mishnah in Shevuos (27a). The logic of the Rabanan is that a Shevu'ah cannot take effect unless it is able to be made both with "Lav v'Hen," (roughly, "in the positive and in the negative") and a Shevu'ah cannot be made to *transgress* a Mitzvah (see 1a:A in the chart).
According to the Ramban (Milchamos, Shevuos 27a and on the Torah, beginning of Matos) and the Rosh, Tosfos, Ritva, and Rambam (Hilchos Shevu'os 5:16), the Rabanan hold that a Shevu'ah to fulfill a Mitzvah b'Kum v'Aseh (i.e. actively) does not take effect at all -- neither for the Chiyuv Korban nor for Malkus. (This is also the implication of Tosfos in Shevuos 23b implies, as REBBI AKIVA EIGER points out in a Teshuvah.) They explain the Gemara in Nedarim (8a) that says that a person may make such a Shevu'ah to motivate himself, "l'Zaruzei Nafshei," to mean that a person is not deemed to be Motzi Shem Shamayim l'Vatalah, or swearing a Shevu'as Shav, in such a case. Regarding a Shevu'ah to observe a Mitzvah through Shev v'Al Ta'aseh, all of the Rishonim agree that the Shevu'ah does not take effect even with regard to Malkus (and certainly not for Korban). Their proof is from the Gemara in Makos (22a), which does not enumerate a ninth set of Malkus (see the Mishnah there) if a person *made a Shevu'ah* not to plow on Shabbos. The reason such a Shevu'ah does not take effect at all (i.e. even for Malkus) is because of Ein Isur Chal Al Isur. (Regarding whether the Shevu'ah takes effect at least with regard to adding an extra degree of Isur, see what we wrote in footnote #7.)

(9) The Ba'al ha'Me'or in Shevuos (end of Perek 3) writes that even though such a Shevu'ah does not take effect with regard to a Chiyuv Korban, nevertheless it does take effect with regard to Malkus. He learns this from the Gemara (Nedarim top of 17a, Shevu'os 25a) that explains that every Shevu'ah that cannot be made both "b'Lav v'Hen" (see footnote #8) is excluded from bringing a Korban but not from Malkus. This is also the view of the Ran in Nedarim (8a).
It seems that the Me'or and the other Rishonim (see above, #8) differ over the reading of the Gemara in Nedarim 16b. According to the Me'or and Ran, Shevu'os to override a Mitzvah do not take effect on logical grounds (i.e. because an Isur Gavra cannot override a Mitzvah of the Torah). According to the Milchamos and others, though, the Torah *excludes* Shevu'os from taking effect on Mitzvos by saying "Devaro," implying that they do not take effect on "Cheftzei Shamayim" (i.e. Mitzvos) even as far as Malkus is concerned. Since the Torah excludes Shevu'os from taking effect on Mitzvos, they are not punishable with Malkus whether the Shevu'ah was to override a Mitzvah or to uphold it (see Milchamos ibid.).