Siman - Yoma Daf 79
- A large date with its pit is bigger than a כביצה
The Mishnah on Daf 73b stated, האוכל ככותבת הגסה כמוה וכגרעינתה חייב – One who eats the equivalent of a large date, the equivalent of it and its pit, is chayav kares. On this Daf, Rabbah said in the name of Rav Yehudah, כותבת הגסה שאמרו יתירה מכביצה – The “large date” mentioned in the Mishnah, is larger than an egg-volume. וקים להו לרבנן דבהכי מיתבא דעתיה – And this unusual measure was established because the Rabbanon knew that with this amount of food one’s mind is put at ease, בציר מהכי לא מיתבא דעתיה – but with less than this amount, one’s mind is not at ease. Rashi explains that the prohibition against eating on Yom Kippur differs from all other prohibitions related to eating. In all other cases, the prohibition is against eating, and anything less than a kezayis does not constitute an act of “eating.” With regard to Yom Kippur, the Torah does not expressly prohibit “eating.” Rather, it commands one to afflict oneself through fasting. When one eats less than a large date his mind is not set at ease, and he remains “afflicted.”
- Fruit does not require a sukkah
The Gemara challenged Rabbah’s assertion that a large date with its pit is larger than a כביצה, based on a Mishnah in Sukkah, where Rabban Gamliel ate two dates in the sukkah as a personal chumrah, whereas Rebbe Tzadok would only eat less than a כביצה outside the sukkah, from which we can infer that a כביצה must be eaten in the sukkah. This implies that a כביצה is even larger than the size of two dates? Rebbe Yirmiyah answered that two dates without their pits are not as large as a כביצה, but one large date with its pit is larger than a כביצה. Rava said, that the reason that eating two dates does not require a sukkah, is not because the meat of the dates is smaller than a כביצה, but because they are fruit, ופירי לא בעו סוכה, and fruit eaten in any volume is considered a snack, which does not require a sukkah.
- כותבת הגסה חסרה מכביצה
Rav Zevid disagrees with Rabbah, and says כותבת הגסה שאמרו חסרה מכביצה – The large date of which the Mishnah spoke, is less than the equivalent of a כביצה. When Rav Zevid’s proof for this is deflected, the Gemara brings a proof from a Mishnah in Berachos, regarding the minimum amount of bread one must eat to be chayav to join a zimun. Rebbe Meir says at least a ,כזית whereas Rebbe Yehudah says at least a כביצה. Rebbe Meir holds that when the passuk states, ואכלת – and you shall eat, this is a reference to eating, and that when the passuk states, ושבעת – and you shall be satisfied, this is a reference to drinking. Since אכילה is a כזית, that is the minimum amount to bless Hashem. Rebbe Yehudah holds that the words ואכלת ושבעת together, mean אכילה שיש בה שביעה – an eating that satisfies, which is the amount of a כביצה. Now if a כביצה satisfies, can it be that it does not put the mind of one who is fasting, at ease? Of course not. Rather, one can derive from here that the large date is smaller than a כביצה, and the difference is that the כביצה satisfies, whereas the כותבת puts the mind at ease but does not satisfy.
