1) THE PROHIBITION OF AN "ISAR"
QUESTIONS: The Beraisa says that the word "Mivta" represents a Shevu'ah, and the word "Isar" represents a Shevu'ah. The Beraisa continues and says that if the utterance of the word "Isar" is like an explicitly-stated Shevu'ah, then one is Chayav, and if it is not like an explicitly-stated Shevu'ah, then one is Patur. The Gemara points out that the Beraisa seems to contradict itself, since it begins by saying that an "Isar" is a Shevu'ah, and then it casts doubt on whether or not it is a Shevu'ah.
Abaye explains that the Beraisa means that the word "Isar" represents a Shevu'ah created through "Hatfasah" (a comparison of one object to another object that was previously prohibited through a Shevu'ah). The concluding words of the Beraisa mean that if making a Shevu'ah through Hatfasah is comparable to making an explicit Shevu'ah, then one is Chayav for his Isar, and if not, the Isar does not obligate the person and he is exempt if he transgresses it.
RASHI explains that when the Gemara says that "Isar" represents a Shevu'ah made through Hatfasah, it means that when a person declares, "This object is an 'Isar' upon me," he is considered as though he prohibited one object through a Shevu'ah and then pointed to a second object and said, "This object is like the first." The doubt of the Beraisa is whether or not Hatfasah creates a Shevu'ah like an explicitly-stated Shevu'ah or not.
The Rishonim point out a number of difficulties with the explanation of Rashi.
(a) How can the Beraisa first assert that the word "Isar" refers to making Hatfasah to an object already prohibited through a Shevu'ah, and then doubt whether Hatfasah creates a prohibition altogether? The verse which Abaye quotes (Bamidbar 30:3) clearly states that an Isar creates a prohibition just as a Shevu'ah does.
(b) How can the Beraisa leave this Halachah in doubt? The normal manner of a Beraisa is to quote the opinions of Tana'im, not to mention a Halachah merely in order to teach that the Halachah is subject to doubt and the ruling in practice is not known. (TOSFOS DH Isar)
(c) Why does Rashi explain that the word "Isar" refers to a person who says, "This object is an 'Isar' upon me"? Such an expression does not seem to be related to Hatfasah at all, since the person does not refer to any previous Shevu'ah. Moreover, such an expression should constitute not a Shevu'ah but a Neder, since the person uses an expression of Neder ("This object is 'Isar' upon me") and not an expression of Shevu'ah ("I shall not eat the object"). (RAMBAN, RASHBA)
Rashi should explain the meaning of "Isar" the way the Beraisa describes it (later on this Daf): "What is the 'Isar' to which the Torah refers? When a person says 'I shall not eat meat... like the day on which his father died' (and on the day that his father died he had vowed not to eat meat)." (TOSFOS)
(d) The Gemara continues and says that Abaye is consistent with his interpretation of the Beraisa when he rules that when a person makes a Hatfasah from a Shevu'ah, he is considered as though he has expressed a Shevu'ah explicitly. Why is this consistent with his interpretation of the Beraisa? The Beraisa remains in doubt about whether or not Hatfasah is like an explicit Shevu'ah. Why is Abaye certain that it is like a Shevu'ah? (TOSFOS)
(a) As the RAMBAN and others point out, the answer to the first question is evident from the words of Rashi. When the Beraisa expresses doubt about whether or not Hatfasah is like an explicit Shevu'ah, it is not questioning whether or not Hatfasah creates an Isur. Rather, Hatfasah certainly creates an Isur of Shevu'ah. This is what the Beraisa means when it states that "Isar is a Shevu'ah." The question is whether Isar is similar to a Shevu'ah with regard to all of the aspects of Shevu'ah. For example, can it obligate a person to receive Malkus or to bring a Korban if he transgresses it? (This view is also evident from the ruling of the RAMBAM in Hilchos Shevu'os 2:8.)
(b) The doubt in the Beraisa may indicate that there was another part to this Beraisa which preceded these words (but which is not quoted by the Gemara). In that first part of the Beraisa, Tana'im argue about whether or not Hatfasah is like an explicit Shevu'ah. The Tana'im in that part of the Beraisa might have been discussing a situation in which a person actually specified a Shevu'ah about one item and then pointed to a second item and said, "This is like the first." The next part of the Beraisa (which the Gemara quotes) then says that since saying "Isar" is equivalent to performing such a procedure, when a person says, "This object is an 'Isar' upon me," the Halachah depends on the Machlokes Tana'im (expressed in the first part of the Beraisa) regarding Hatfasah of a Shevu'ah. The Tana who considers Hatfasah an explicit Shevu'ah will also considered an Isar an explicit Shevu'ah, while the Tana who does not consider Hatfasah an explicit Shevu'ah will rule the same way with regard to Isar. (M. KORNFELD)
(c) The answer to the second question also answers Tosfos' question. According to Rashi, the case of an Isar cannot refer to a person who prohibits an item with a Shevu'ah and then prohibits a second item "like the first," because that is the normal case of Hatfasah, and from the Beraisa it is clear that the concept of Isar is an extension of the law of Hatfasah and it is not the actual case of Hatfasah (about which the Tana'im argue).
How does the word "Isar" imply that the person wants this object to be as though it is connected to another object that previously was made prohibited through a Shevu'ah? How does it imply that there is a second object involved?
The RAMBAN explains that "Isar" literally means "bound" or "tied together," as in the verse, "Osri la'Gefen Iro" -- "He will tie his donkey to the vine" (Bereishis 49:11), and in other verses. The usage of this word implies that this object is bound to another object that previously was prohibited (through a Shevu'ah).
Why, though, does Rashi explain that the case of Isar is when a person says, "This is an 'Isar' upon me"? Why does he not explain that the case of Isar is when one says, "'Isar' that I will not do this"?
To understand this, it is necessary to analyze the difference between Hatfasah and an explicit Shevu'ah. Why should the Isur of Hatfasah be any less binding than that of an explicit Shevu'ah? Rashi (beginning of 20b, DH Taritz) implies that the difference is that when one expresses Hatfasah, he does not mention the word "prohibited." He says merely, "This [object] is like this [other object]." That is, in a case of Hatfasah, the person never states that he will not eat the object. He simply says that the second object is like the first. He becomes prohibited from eating the second object because his second statement implies that he will not eat it, and he is obligated by the Mitzvas Aseh of keeping one's word ("k'Chol ha'Yotzei mi'Piv Ya'aseh," Bamidbar 30:3). However, not all Tana'im agree that he will be obligated because of the prohibition of Shevu'as Sheker since, by definition, a Shevu'ah might mean specifying explicitly that the object is prohibited.
This is why Rashi explains that the case of Isar is not when a person says, "'Isar' that I will not do this," but rather he simply says, "This object is an 'Isar' upon me."
If this is true, however, then why does the Beraisa say that "Mivta" is like an explicit Shevu'ah, while "Isar" is only Hatfasah? If a person says "this item is a 'Mivta' upon me," it should not be like a Shevu'ah since he did not mention the word "prohibited." Also, why is "Isar" the only term that may be used to express Hatfasah? The same Halachah of Hatfasah should apply when a person says, "This object is a 'Shevu'ah' upon me."
The answer is that "Isar" is the only term that implies "binding" two objects together (as mentioned above). Therefore, when a person says "Isar," his words (comparing one object to another one) may be interpreted as the creation of a prohibition without the need for an explicit mention of prohibiting the object. In contrast, the words "Shevu'ah" and "Mivta" have no implication of binding one object to another. Hence, if a person uses such terms, the only possible interpretation is that he really wants to prohibit the object with a Shevu'ah. Consequently, he is considered as though he said explicitly, "I want this object to be prohibited to me with a Shevu'ah."
(Rashi maintains that a Shevu'ah may be uttered using the terminology of a Neder, in contrast to the view of other Rishonim. See Rashba to Nedarim 2b.)
(d) How does Abaye know that the Halachah is that Hatfasah is like a Shevu'ah with regard to Malkus and Korban? Perhaps he learns from the wording of the Beraisa -- which places the opinion that Hatfasah is like a Shevu'ah before the possibility that Hatfasah is not like a Shevu'ah -- that the first part of the Beraisa (which lists the opinions regarding Hatfasah) attributes the majority opinion to those who maintain that Hatfasah is like a Shevu'ah, and thus Abaye rules accordingly.
2) ONE WHO PROHIBITS HIMSELF FROM EATING LIKE HE WAS PROHIBITED FROM EATING ON "TZOM GEDALYAH"
QUESTIONS: The Beraisa says that a person can create a Neder by saying, "I will be prohibited from eating today just as I was prohibited from eating on the day that Gedalyah ben Achikam was killed." Shmuel adds that the Neder takes effect only if the person previously prohibited himself from eating on Tzom Gedalyah with a Neder. The Gemara says that the Beraisa means to teach that even though a person is prohibited from eating on that day even without the Neder, his present Neder nevertheless takes effect. One might have thought that when a person prohibits himself from eating by saying, "just as I was prohibited to eat on the day that Gedalyah ben Achikam was killed," he intends to prohibit himself with an Isur similar to the Isur d'Rabanan of eating on that day, and not with a Neder. The Beraisa therefore teaches that his Neder takes effect and is considered Hatfasah, because he intends to prohibit himself in a way similar to the Isur Neder of that day.
RASHI writes that there was another Girsa in the Gemara, according to which the Gemara says that the only reason why the Hatfasah creates an Isur is that Tzom Gedalyah is an Isur d'Rabanan, and therefore his Neder not to eat on Tzom Gedalyah takes effect. According to that Girsa, if Tzom Gedalyah would have been an Isur d'Oraisa, then his Neder would not have been able to take effect, because a Neder cannot prohibit what the Torah already prohibits.
Rashi rejects this Girsa, pointing out that the Gemara earlier (25a) says that a Neder can take effect even to override a Mitzvah d'Oraisa, and, therefore, a Neder to fulfill a Mitzvah (such as not to eat on Yom Kippur) will take effect as well.
There are a number of difficulties with Rashi's explanation.
(a) If the Neder would have taken effect to prohibit him from eating even on a day on which the Torah prohibits him from eating, then why does the Beraisa give the example of a person who makes a Neder to prohibit himself from eating just as he is prohibited on Tzom Gedalyah? The example of such a Neder should have been one who prohibits himself from eating just as he prohibited himself with a Neder from eating on Yom Kippur! (RAMBAN, RASHBA)
(b) There is a principle that "Ein Isur Chal Al Isur" -- once an object is prohibited with an Isur Torah, it cannot become prohibited again with another Isur Torah. Therefore, even if the Mishnah says that a Neder can override a Mitzvah and obligate a person to transgress a Mitzvah of the Torah, nevertheless a Neder should not take effect to prohibit a person in what the Torah already prohibits him, because "Ein Isur Chal Al Isur." Why should a Neder be different from any other Isur in the Torah? (TOSFOS)
(a) Perhaps the Beraisa gives the example of a person who prohibited himself with a Neder from eating on Tzom Gedalyah and did not prohibit himself with a Neder from eating on Yom Kippur, because it is uncommon for a person to prohibit himself with a Neder from eating on Yom Kippur since he is already prohibited to eat on that day by the Torah. The Beraisa mentions the more common example.
(b) With regard to the question from the rule of "Ein Isur Chal Al Isur," the simple answer is that Rashi understands the Gezeiras ha'Kasuv of "Neder la'Hashem" (Bamidbar 30:3) -- which teaches that a personal Neder can override a Mitzvah (Nedarim 16b) -- to be a blanket, general Gezeiras ha'Kasuv that states that a Neder can take effect regardless of what the Torah says. This Gezeiras ha'Kasuv removes Nedarim from the normal rule of "Ein Isur Chal Al Isur."
However, the RAN in Nedarim (18a) offers a logical distinction, in addition to the Gezeiras ha'Kasuv, between Nedarim and other Isurim of the Torah. The Ran cites the Gemara in Nedarim (2b) which teaches that a Neder creates an Isur Cheftza (the object becomes prohibited), while a Shevu'ah creates an Isur Gavra (the person becomes prohibited from performing a specific action). The Ran explains that most Isurim of the Torah are Isurei Gavra; they prohibit the person from performing a specific act, or they obligate him to perform a specific act. A Neder, aside from being an Isur Gavra like every other Isur in the Torah, also creates an Isur Cheftza, making the object of the Neder into a prohibited object (like a Korban, which has the distinction of being Kadosh). Normally, an Isur cannot take effect when a previous Isur exists, because the Isurim of the Torah were not given to reinforce what was previously prohibited. A Neder, however, does not merely reinforce what was prohibited previously; it also creates something that did not exist previously -- an Isur Cheftza, a prohibition on the object. Since the Isur of Neder adds something that did not exist previously, it can take effect to prohibit a person from something that the Torah already prohibits.
The BA'AL HA'ME'OR (27a) asks a strong question on Rashi's opinion that a Neder can prohibit an action that was already prohibited. The Mishnah in Makos (21b) lists eight Isurim that a person can transgress with a single act of plowing. Rebbi Ze'ira (Makos 22a) asks why the Mishnah does not list an additional prohibition that can be transgressed in the same act: the prohibition of Shevu'ah, such as when the person prohibited himself with a Shevu'ah from plowing. The Gemara answers that the Mishnah includes, among the eight transgressions, the act of plowing on Yom Tov, a day on which the Torah prohibits plowing. Since it was Yom Tov, the Gemara asserts, the Shevu'ah cannot take effect, because a Shevu'ah cannot take effect to prohibit a person in what the Torah already prohibits him. Rebbi Ze'ira asks that the Mishnah still should have added the prohibition of Shevu'ah by mentioning a case in which a person prohibited upon himself plowing both on Yom Tov and during the week, making it an Isur Kollel. When there is an Isur Kollel, the Shevu'ah does take effect to prohibit something that was already prohibited! The Gemara concludes that the Mishnah must be following the opinion that does not allow a second prohibition to take effect, even if the second prohibition is an Isur Kollel.
The Ba'al ha'Me'or asks that according to Rashi, Rebbi Ze'ira should have asked another question: the Mishnah should include a case in which the person prohibited himself with a Neder from using the plow, since, according to Rashi, a Neder does take effect to reinforce a previously-existing prohibition, even when the Neder is not an Isur Kollel! This seems to be a very strong refutation on Rashi's assertion.
The RAMBAN (in Milchamos) suggests a forced answer, that the Gemara indeed could have given this example of a ninth prohibition that a person could transgress while plowing, but since it already produced a long list of other possible transgressions (see Makos there), the Gemara did not bother to add this possible transgression.
However, according to the logic cited above in the name of the Ran in Nedarim, a more basic answer may be suggested. The reason why a Neder takes effect when a prohibition already exists is that the Neder is adding a new dimension to the prohibition -- an Isur Cheftza. In this sense, it is similar to an Isur Kollel (or Isur Mosif). Once the Gemara establishes that the Mishnah in Makos follows an opinion that does not accept the rule that an Isur Kollel (or Mosif) can take effect on a previous prohibition, it follows that an Isur Neder also will not take effect on a previous prohibition.
3) THE PROHIBITION OF VIOLATING ONE'S OATH
QUESTION: Rav Dimi says in the name of Rebbi Yochanan that a person who swears that he will eat (or not eat) and then violates his Shevu'ah is guilty of transgressing the prohibition of "v'Lo Sishav'u vi'Shemi la'Shaker" (Vayikra 19:12), while a person who transgresses a Konam (Neder) violates the prohibition of "Lo Yachel Devaro" (Bamidbar 30:3). The words of Rav Dimi imply that the prohibition of "Lo Yachel Devaro" does not apply to a Shevu'ah but only to a Neder. How can he make such an assertion? The verse of "Lo Yachel Devaro" explicitly states, "If a man makes a Neder to Hash-m, or swears a Shevu'ah to create a prohibition upon himself, he may not violate his word (Lo Yachel Devaro)"! It is clear from the verse that the prohibition applies equally to a Neder and to a Shevu'ah. (TOSFOS DH Konamos)
(a) TOSFOS explains that Rav Dimi's intention is not to limit "Lo Yachel Devaro" to a Neder, because the verse clearly prohibits violating a Shevu'ah. Rather, he means that the only new prohibition learned from "Lo Yachel" is the prohibition of Neder, since the prohibition of a Shevu'ah is known already from "v'Lo Sishav'u vi'Shemi la'Shaker."
RASHI (DH Konamos), however, writes that "Lo Yachel" does not refer to the prohibition of violating one's Shevu'ah l'Haba (an oath to do, or not to do, something in the future).
However, the RITVA explains that Rashi, too, intends to make the same point as Tosfos -- that "Lo Yachel" is not needed to teach the prohibition of Shevu'ah, since the prohibition is learned from "v'Lo Sishav'u vi'Shemi la'Shaker." However, one who violates his Shevu'ah certainly is also guilty of transgressing the prohibition of "Lo Yachel Devaro."
Nevertheless, this view does not seem to be accepted by all. The RAMBAM (Lo Sa'aseh #157) and the CHINUCH (Mitzvah #407) write clearly that "Lo Yachel" prohibits a person from violating a Neder and not a Shevu'ah. They seem to understand the words of Rav Dimi literally. (See also the Rambam's abridged listing of Mitzvos at the beginning of Yad ha'Chazakah.) In fact, the Rambam elsewhere (Hilchos Shevu'os 1:3) writes that one who violates his Shevu'ah receives Malkus only for transgressing "v'Lo Sishav'u vi'Shemi la'Shaker." The KESEF MISHNEH there asserts that one who violates a Shevu'ah also transgresses "Lo Yachel Devaro" according to the Rambam. However, the Rambam in Sefer ha'Mitzvos (Shoresh Teshi'i) maintains that a person does not receive an extra set of Malkus when the Torah prohibits a single act with two Lavim (unless there is an explicit Kabalah otherwise).
However, the MINCHAS CHINUCH (227:1) points out that this interpretation is inconsistent with the words of the Rambam in Hilchos Nezirus (1:2), who writes that a Nazir who drinks wine is punished with two sets of Malkus, one set for "Lo Yachel Devaro" and one set for the Lav of Nazir. It is clear that "Lo Yachel Devaro" is not treated as a second, reinforcing Lav, but rather as an entirely new Mitzvah. This indeed is logical, because "Lo Yachel Devaro" is not simply a repetition of the prohibition of Shevu'ah, as it includes many more laws, such as Neder and Nezirus. Conversely, the prohibition of Shevu'ah includes acts that are not included in the prohibition of "Lo Yachel Devaro," such as Shevu'as Sheker l'she'Avar (swearing falsely about a past action). Accordingly, if the Rambam indeed maintains that "Lo Yachel Devaro" applies to Shevu'ah, then he should write in Hilchos Shevu'os as well that a person receives two sets of Malkus for violating a Shevu'ah.
Therefore, it seems clear that according to the Rambam, "Lo Yachel" applies only to Nedarim, as the straightforward reading of the Gemara implies. How, though, does he understand the fact that the verse of "Lo Yachel Devaro" mentions Shevu'ah? The Rambam himself seems to address this in Sefer ha'Mitzvos. From the Rambam's wording there, it appears that he maintains that when the verse says "O Hishava Shevu'ah," it does not refer to a person who prohibited something upon himself with a Shevu'ah. Rather, it refers to a person who obligated himself to do or not to do a particular action by saying, "This object will be prohibited upon me if I do or fail to do such-and-such an action." The verse uses the word "Shevu'ah" to describe this prohibition since the person has created a Isur Gavra through his Neder, similar to the Isur of Shevu'ah.
This interpretation sheds new light on the Gemara in Nedarim (3b) which states that a person transgresses "Lo Yachel Devaro" when he makes a Neder that he will eat a loaf of bread and then fails to eat it. REBBI AKIVA EIGER (in Gilyon ha'Shas there) points out that this is not consistent with the rules of Neder, which limit a Neder to a prohibitory statement. According to the Rambam, such a Neder indeed is written explicitly in the verse of "Lo Yachel Devaro." (M. KORNFELD)