QUESTION: Rava (end of 27b) says that one who swears that he will not eat a loaf of bread and then he eats almost all of it, but leaves over a k'Zayis, may still rescind his Shevu'ah through She'eilah. RASHI (DH Nish'al) explains that the annulment of his Shevu'ah permits him to eat the remaining k'Zayis, and it exempts him retroactively for the part of the bread that he already ate. If, however, he ate all of the loaf of bread, he has transgressed the Shevu'ah and no longer may annul it.

Rav Acha brei d'Rava asked Rav Ashi exactly what words were used in the Shevu'ah in this case. If the person said, "I will not eat," then as soon as he ate the first k'Zayis he transgressed the prohibition (as stated by Rava himself on 27b). If he said, "I will not eat it," he transgresses his Shevu'ah only when he eats the entire loaf.

Rav Ashi answered that the person swore, "I will not eat." Since he is able to annul the Shevu'ah so that it does not prohibit the last k'Zayis that remains, his annulment also is effective to retroactively permit the parts of the loaf that he already ate. Rashi (DH Migu) explains that since, when a Chacham annuls an oath, he essentially annuls it from when it was first stated, retroactively there was no Shevu'ah when the person ate the first k'Zayis.

This Gemara seems to contradict the ruling of the RAMBAM (Hilchos Shevu'os 4:1) and SHULCHAN ARUCH (YD 238:1). The Rambam writes, "One who swears that he will not eat anything today and then he eats less than a k'Zayis is exempt from a Korban, because eating less than a k'Zayis is not considered an act of eating. This is equivalent to eating half a Shi'ur of Neveilos or Tereifos, or similar prohibitions."

The Rambam clearly compares the law of a Shevu'ah to the law of other prohibitions. If the law of Shevu'ah is the same as the law of other prohibitions, then why does the Gemara here say that since the Shevu'ah's annulment is effective for the remaining k'Zayis, it is effective for the rest of the loaf of bread that the person ate? The Halachah is that "Chatzi Shi'ur Asur Min ha'Torah" -- the Torah forbids even a partial Shi'ur of a prohibited item (see Yoma 73b). The Gemara should say that since the annulment is effective to permit the last half (or even less) of a k'Zayis, it permits the entire loaf of bread, since, as the Rambam says, there is still a Torah prohibition against eating the last half-k'Zayis! If Chatzi Shi'ur is Asur Min ha'Torah, why does Rava say that one may annul the Shevu'ah retroactively only when a k'Zayis of the loaf (and not less) remains?

ANSWER: REBBI AKIVA EIGER (Teshuvos 1:154, and as cited in CHIDUSHEI REBBI AKIVA EIGER, end of 22b) answers that perhaps "Chatzi Shi'ur Asur Min ha'Torah" applies only when a full k'Zayis remains from the prohibited object. The Gemara in Yoma (74a) explains the reason why Chatzi Shi'ur is Asur Min ha'Torah: it is "Chazi l'Itzterufi" -- it is fit to join together with other small amounts and become a proper Shi'ur. In contrast, one who eats the entire loaf of bread except for half of a k'Zayis cannot become liable by eating the last half-k'Zayis, because there is no other half-k'Zayis of the loaf with which it can combine to make a full Shi'ur. (This is in contrast to an ordinary case of a Chatzi Shi'ur, where one who eats a half-k'Zayis of a forbidden food such as Neveilah or Tereifah can always eat more Neveilah or Tereifah that exists in the world, so that he eats a full k'Zayis.) Therefore, the Rambam will agree that mid'Oraisa one is permitted to eat the last half-k'Zayis of the loaf (without annulling the Shevu'ah). Accordingly, it is not possible to annul the oath when less than a k'Zayis remains, and thus the Gemara does not discuss annulling the oath when less than a k'Zayis remains.

Rebbi Akiva Eiger adds that according to this logic, if one eats half a k'Zayis of Chametz at the very end of Pesach when there is no time left to eat a second half-k'Zayis (or one eats half of a Koseves of food at the very end of Yom Kippur), he does not transgress the Torah prohibition of Chatzi Shi'ur. (D. BLOOM)

QUESTION: The Gemara relates that Eifa learned Maseches Shevuos in the Yeshiva of Rabah. His brother Avimi asked him a number of questions. His second question involved a person who swore, "I will not eat nine figs," and then swore again, "I will not eat ten figs." What is the law? Eifa answered that the person is liable for each Shevu'ah.

RASHI (DH she'Lo Ochal) explains that the person ate ten figs without remembering his Shevu'ah. Eifa mistakenly thought that the second Shevu'ah is not included in the first Shevu'ah (because ten is more than nine), and thus he did not say that the second Shevu'ah cannot take effect once the first Shevu'ah was made.

Avimi told his brother, "You are wrong! If he cannot eat nine, then certainly he cannot eat ten." Rashi (DH Ishtabesht) explains that when the person's Shevu'ah not to eat nine figs already forbids him from eating ten, because if he does not eat the first nine he cannot eat the tenth. Therefore, the second Shevu'ah does not take effect, because it prohibits something which a pre-existing Shevu'ah already prohibits, and the rule is that "Ein Shevu'ah Chalah Al Shevu'ah" (see Nedarim 8a). Only the first Shevu'ah is valid, and the person is liable for only one Shevu'ah.

Avimi asked Eifa another question. If a person swore, "I will not eat ten," and then swore, "I will not eat nine," what is the law? Eifa replied that he is liable for only one Shevu'ah. Avimi again told his brother, "You are wrong! When he made the first Shevu'ah, he prohibited himself only from eating ten, but he was still permitted to eat nine."

Rashi (DH Eino) explains that Eifa's mistake was that he assumed that since nine is less than ten, the second Shevu'ah is automatically included in the first. However, in truth the first Shevu'ah prohibited him only from eating ten, but he was still permitted to eat nine. Therefore, the second Shevu'ah created a new prohibition against eating nine, and thus it was able to take effect. Accordingly, when he eats nine he transgresses the second Shevu'ah, and when he eats the tenth he transgresses the first Shevu'ah.

Abaye says that there is a case in which Eifa's ruling is correct. Rashi (DH Zimnin) explains that Abaye refers to where the person swore not to eat ten and then not to eat nine. In such a case, he is liable for only one Shevu'ah.

Abaye says that this is similar to Rabah's case. Rabah discusses the case of a person who swore not to eat figs and grapes, and then he swore again not to eat figs. He accidentally ate figs, and separated a Korban for his transgression of the second Shevu'ah. Afterwards he ate grapes. Rabah rules that he is exempt from a Korban for eating the grapes because it is only a Chatzi Shi'ur (grapes constitute only half of the prohibition of the first Shevu'ah). Rashi (DH v'Ochal) explains that since he separated a Korban for eating the figs, the grapes no longer combine with the figs to make him liable for transgressing the first Shevu'ah.

The Gemara says that this is similar to a case in which a person swore that he would not eat ten figs, and then he swore not to eat nine figs. If he accidentally eats nine figs and separates a Korban for his transgression of the second Shevu'ah, and afterwards he eats the tenth fig, he is exempt from further liability. The tenth fig is only a Chatzi Shi'ur, since the first nine figs cannot combine with it once he already separated a Korban for eating them. This is the case in which Eifa's ruling is correct.

TOSFOS (DH Shevu'ah) cites a variant text of Rabah's statement, according to which the person first swore that he would not eat figs, and then he swore that he would not eat figs and grapes.

However, this text is problematic. If, when he made the second Shevu'ah, his intention was not to eat either figs by themselves or grapes by themselves, then it is not appropriate for the Gemara later to refer to grapes as a Chatzi Shi'ur. If, on the other hand, his intention was to forbid himself from eating figs and grapes together, the second Shevu'ah should not take effect at all. In such a case, Avimi's objection would apply: "If he cannot eat nine, then certainly he cannot eat ten." Since his first Shevu'ah forbids him from eating figs, his second Shevu'ah not to eat figs and grapes does not take effect since figs are already forbidden to him.

What, then, is the intention of Tosfos' text, that the first Shevu'ah was on figs and the second Shevu'ah on figs and grapes? What is the difference between this case and the case in which one makes a Shevu'ah not to eat nine figs, followed by a Shevu'ah not to eat ten figs, in which case the second Shevu'ah does not take effect?

ANSWER: TOSFOS (beginning of 29a) answers that there is a distinction between "nine and ten" and between "figs and grapes." In the case of "nine and ten," when the person made the first Shevu'ah not to eat nine figs, his Shevu'ah prohibited him from eating any nine figs. Therefore, he is already forbidden to any nine figs that he will eat out of ten (which he prohibited with the second Shevu'ah). When he made the second Shevu'ah not to eat any ten figs, he was already forbidden from eating all of the figs in the world that would add up to nine, and certainly to ten. The second Shevu'ah therefore cannot take effect, because "Ein Shevu'ah Chalah Al Shevu'ah."

In contrast, in the case of "figs and grapes," his first Shevu'ah not to eat figs did not refer to grapes at all. Therefore, the second Shevu'ah on figs and grapes can apply. Since the second Shevu'ah applies for grapes, it also applies for figs. This concept is taught in the Gemara in Nedarim (17b).

Tosfos adds that according to this logic, if a person makes a Shevu'ah not to eat "these nine figs" (specifying which figs are forbidden), and then he makes a Shevu'ah not to eat ten figs, the second Shevu'ah takes effect, because it is valid for the tenth fig from which he was not previously forbidden. Consequently, the second Shevu'ah also takes effect for the first nine figs. (See also KEHILOS YAKOV #23.) (D. BLOOM)