1) FASTING ON SHABBOS
QUESTION: The Gemara relates that Mar brei d'Ravina fasted on every day of the year, except for Shavuos, Purim, and Erev Yom Kippur. Those are days on which one is required to eat, as the Gemara explains.
The Gemara implies that these three days were the only days on which Mar brei d'Ravina did not fast, and that he fasted on every other day of the year, including Shabbos and Yom Tov. How could he fast on Shabbos and Yom Tov? Fasting on Shabbos is prohibited, as the Gemara here quotes in the name of Rabah. Fasting on Yom Tov should also be prohibited, because the Gemara earlier quotes Rebbi Yehoshua who says that one is required to eat on Yom Tov, and the Halachah normally follows Rebbi Yehoshua and not Rebbi Eliezer ("Shamuti") when they argue.
(a) The BA'AL HA'ME'OR writes that the practice of Mar brei d'Ravina teaches that one is permitted to fast on Yom Tov, and that the Halachah follows Rebbi Eliezer who says that one is not required to eat on Yom Tov. (This is also the opinion of the MORDECHAI, Shabbos 1:230.)
According to the Ba'al ha'Me'or, Mar brei d'Ravina did not fast on Shabbos (even though the Gemara does not mention this explicitly), because even Rebbi Eliezer maintains that one must eat on Shabbos, as Rabah states.
The RA'AVAD cites RAV HAI GA'ON who concludes in his first approach that the Halachah follows the opinion of Rebbi Eliezer, like the Ba'al ha'Me'or. He adds, however, that Mar brei d'Ravina argues with Rabah and maintains that one is permitted to fast on Shabbos according to Rebbi Eliezer.
(b) The RA'AVAD himself disagrees and writes that the Halachah does not follow Rebbi Eliezer, but rather Rebbi Yehoshua. When the Gemara says that Mar brei d'Ravina fasted all year, it means that he accepted upon himself to fast throughout the year on every Monday and Thursday, as is customary for righteous people to do. At the time that he accepted this practice upon himself (with a Neder, a vow), he remembered to specifically exclude the three days mentioned in the Gemara as exceptions, but he did not specify any other exceptions. Therefore, if any other Yom Tov fell on Monday or Thursday, he fasted because of his Neder. (The Neder overrides the obligation to eat on Yom Tov. Even though a Neder normally cannot uproot a Mitzvah, in this case the Neder does not directly contravene the Mitzvah. Mar brei d'Ravina did not vow to fast specifically on Yom Tov, but rather to fast on Mondays and Thursdays.)
In a similar explanation, TOSFOS in Berachos (49b, DH Iy Ba'i Achil) writes that Mar brei d'Ravina did not fast every day of his life. Rather, whenever he had a bad dream he observed a "Ta'anis Chalom" -- a fast to annul the Divine decree that a bad dream represents -- on any day of the year. One is permitted to observe a Ta'anis Chalom even on Shabbos and Yom Tov (Shabbos 11a). Mar brei d'Ravina was careful, however, not to observe even such a fast on the three days mentioned in the Gemara.
According to the approach of Tosfos, the practice of Mar brei d'Ravina does not prove that the Halachah follows Rebbi Eliezer, because even Rebbi Yehoshua agrees that one is permitted to observe a Ta'anis Chalom on Shabbos.
(c) In his final approach, RAV HAI GA'ON concludes that Mar brei d'Ravina was not necessarily following Rebbi Eliezer's opinion. He fasted on Shabbos and Yom Tov because something traumatic once happened to him, for which he resolved to fast every day for the rest of his life as an act of repentance. A fast for repentance is permitted even on Shabbos, because if one does not fast he will experience more distress (since he will feel that he is lacking repentance and atonement). In such a case, fasting is this person's form of Oneg, pleasure, on Shabbos.
Similarly, RABEINU DAVID explains that Mar brei d'Ravina did not specifically accept upon himself to fast every day. Rather, he merely happened to go without eating during the day because he was so involved in his Torah learning, and he would not eat until he came home from the Beis Midrash at night. Since his life's joy was the study of Torah, he was permitted to go without eating on Shabbos, because that itself was his Oneg Shabbos, his Shabbos pleasure. On Yom Tov, too, spending the entire day learning Torah was his form of Simchas Yom Tov, experiencing joy on the festival.
Even though Rebbi Yehoshua requires that one partake in food and drink on Yom Tov in order to experience personal Simchah ("Lachem"), he agrees that one fulfills this requirement if he experiences so much Simchah in learning Torah that he experiences no physical discomfort as a result of not eating (RAV MORDECHAI GIFTER, zt'l, cited in a footnote to Rabeinu David).
The HAGAHOS MAIMONIYOS (Hilchos Ta'anis 1:2) similarly explains that Mar brei d'Ravina's fasts were based on abnormal circumstances. He writes that Mar brei d'Ravina was accustomed to fasting throughout the year, and if he would eat (even on Shabbos) it would upset his stomach (see Bava Basra 146a, "Shinuy Veses Techilas Choli"). Therefore, he was permitted to fast on Shabbos, because eating on Shabbos would be a change from his normal dietary routine and would cause him to be ill. Fasting was his form of Oneg on Shabbos.
HALACHAH: The SHULCHAN ARUCH (OC 288:2) writes that "some say" that one may fast on Shabbos if eating causes him harm, because the fast itself is considered his Shabbos pleasure. Similarly, if one fasts all year and, therefore, eating on Shabbos will cause him to become sick, he is permitted to fast (288:3), as the Hagahos Maimoinyos writes.
One is permitted to observe a Ta'anis Chalom on Shabbos, but one who does so must observe an additional fast on a weekday in order to atone for denying himself Oneg on that Shabbos (288:4). However, others maintain that nowadays we are not expert in understanding the meaning of dreams, and thus one should not observe a Ta'anis Chalom on Shabbos (288:5).
With regard to Yom Tov, the Halachah follows Rebbi Yehoshua (OC 529:1) who maintains that one is required to eat on Yom Tov. (The exceptions enumerated above for eating on Shabbos also apply to Yom Tov.)
2) EATING AND DRINKING ON SHAVUOS
QUESTION: The Gemara says that even Rebbi Eliezer -- who maintains that one's activities on Yom Tov may be dedicated exclusively to Hash-m with no personal physical pleasure -- agrees that there are three days on which one must experience physical pleasure as well: Shavuos, Shabbos, and Purim. The Gemara explains the reason for each one: Shavuos is the day on which the Torah was given. Shabbos requires "Oneg Shabbos" as the verse commands. Purim is a day of "celebration and joy."
The reasons for the requirement to eat and rejoice on Shabbos and Purim are straightforward. Why, though, does the fact that the Torah was given on Shavuos require one to eat and experience physical pleasure on that day? On the contrary, the day on which the Torah was given should be a day completely dedicated to Hash-m. It would seem that the appropriate way to show our appreciation for the Torah would be to spend the entire day immersed in Torah study.
Moreover, the Mishnah in Avos (6:4, 6:6) teaches that "the way of Torah" is for one to eat only bread with salt and to minimize his physical pleasures. Why, then, is the festival of Shavuos not completely dedicated to spiritual activities?
(a) The festival of Shavuos is not designated as the day that celebrates learning Torah, but rather the day that celebrates the receiving of the Torah, Kabalas ha'Torah. In fact, all three days that the Gemara mentions are days of Kabalas ha'Torah. The Gemara in Shabbos (88a) teaches that on Purim, the Jewish people renewed their acceptance of the Torah. Shabbos was the day of the week on which the Torah was given (ibid.), and that is why we mention Kabalas ha'Torah in the Shemoneh Esreh on Shabbos morning.
On the days that represent Kabalas ha'Torah, we must eat and experience pleasure in order to show that the Torah is not a burden to us. Fasting, and avoiding physical pleasure on those days, would show that we feel that observing the Torah is a burden. Therefore, on the day on which we received the Torah, we must emphasize our joy by celebrating and experiencing pleasure.
This is the same reason why Rav Yosef, who was blind, made a festive meal when he learned that a blind person is obligated to fulfill the Mitzvos (Kidushin 31a, Bava Kama 87a). He wanted to show that he was happy to be obligated in Mitzvos. Similarly, a young man's Bar Mitzvah is celebrated with a festive meal to show his joy in accepting the Torah and Mitzvos. (M. KORNFELD)
(b) The Torah was given to man in order to enable him to utilize the physical world in the service of Hash-m. A Jew is not supposed to live an ascetic life, severed entirely from the physical pleasures of the material world. Hash-m placed the Jew's Neshamah into a physical body, fusing the holy with the mundane and charging him with the obligation to uplift and sanctify his physical existence and the physical world in which he lives. The Torah enables the Jew to sanctify the physical world, in contrast to the Nochri who does not have the ability to uplift the physical world and infuse it with spirituality. The Nochri's spirituality is divorced from the physical world. For example, the Nochri's spiritual leaders practice celibacy, while the Kohen Gadol is obligated to be married when he performs the holiest service on the holiest day of the year (Yoma 1:1). It is therefore logical that on the day on which we received the Torah, which teaches us how to utilize the physical world in the service of Hash-m, we are to partake in physical pleasures of food and drink. (Heard from Rav Kalman Weinreb, shlit'a.)