Running on Empty

Running on Empty

by Eliezer Segal

For many centuries, Jewish communities in the diaspora have been adding extra days to most of the festivals ordained in the Torah. This practice originated back in the days when the beginning of each month was determined by the sighting of the new moon, so that it might take a few weeks before messengers could arrive at outlying communities to inform the residents when the current month began and, by extension, what were the dates of any festivals that fell during that month. The policy of two-day holidays remained in force even after the Jewish world adopted a calculated calendar and there was no longer any real doubt about the correct dates.

The exception to this practice was Yom Kippur. Presumably, the prospect of a forty-eight hour fast was deemed too burdensome to impose on the constitutions of Jews for the sake of an anachronistic custom.

The Talmud, however, relates that a number of prominent Babylonian rabbis did observe two-day fasts on Yom Kippur because of doubts as to whether their own calendrical calculations corresponded to those of the official authorities in the holy land. Rabbah did so routinely, and on one occasion it turned out that his fears were justified. In a similar vein, Rav Naḥman was once informed, after what he had thought was the conclusion of Yom Kippur, that the fast would actually be observed in Israel on the following day. He was not pleased to hear this news.

Now, the type of situations that were dealt with by those Babylonian sages should not have arisen if they had access to an agreed-upon system for calculating the Hebrew calendar. Indeed, while historians are uncertain when the calculated calendar was adopted—it was apparently a gradual process that lasted several centuries—it is reasonable to suppose that it was not yet in widespread use in the early fourth century, in the days of Rabbah and Rav Naḥman.

By the medieval era, after the calculated calendar had gained widespread acceptance, there were rabbis who were determined to project the institution back to much earlier times. No doubt, this attitude was motivated by contemporary concerns. The authority to issue ad hoc declarations about the new moon or leap years was an important indicator of the supremacy of the Jewish religious leadership in the land of Israel, and it therefore functioned as a powerful precedent in their ongoing rivalry with the rabbis of Babylonia. Furthermore, the Karaites were alleging that this newfangled rabbinic calendar was yet another example of how the so-called “oral tradition” was nothing more than a fabrication of the rabbis. It is not all that surprising, therefore, that some Babylonian rabbis made exaggerated claims about how the calculated calendar had been in use since time immemorial.

This background helps explain a responsum attributed to a Babylonian Ga’on who was asked to explain the Talmud’s account of Rabbah’s two-day fast: if Rabbah was relying on the same calendar that is in current use, then what possible doubts or discrepancies could have arisen about the date? 

The Ga’on commenced his response by reaffirming that the calculated calendar can be traced back to the era of the biblical prophets. Therefore it is inconceivable that Rabbah would have observed Yom Kippur on a different date; if so, the Talmud must be speaking of a different fast day—the fast of the Ninth of Av which is not from the Torah—and the additional day was nothing more than a personal stringency that Rabbah chose to impose upon himself. 

Another responsum by a Ga’on presented a similar argument, stressing that both Rabbah and Rav Naḥman were acting beyond the requirements of the normative law, certainly not with a view to establishing precedents that should be emulated by the community at large.

Nevertheless, the observance of a second Day of Atonement is attested in several other localities during medieval times. For example, an author from the school of Rashi in northern France reported, “I heard about the eminent scholars Rabbi Judah ben Rabbi Baruch and Rabbi Isaac ben Levi that they would fast on the day following Yom Kippur, and their children and disciples still observe that practice.” The author however issued a warning: It appeared that some of those who believed in a two-day fast were actually tasting some food on the intervening night. This, he insisted, is not proper. Once they have decided to treat the second day as a real biblical holy day, they must also accept all its stringencies; so the fast must continue without respite for more than forty-eight hours. Furthermore, at the conclusion of the second day, those people must even refrain from partaking of food that was prepared for them by Jews who were observing only the one day.

Some authorities insisted that after a person has demonstrated one time that he regards the second day as obligatory, he thereby becomes permanently committed to its observance, and must continue to keep it in all subsequent years. Violators will be subject to “karet,” a divinely imposed death penalty, for transgressing what has acquired for them the status of a commandment from the Torah.

One halakhic compendium explained that a second day of Yom Kippur was really the norm according to proper Jewish religious law, and was observed as such by many prominent persons in the diaspora; it was only out of consideration for the fact that so many people are physically incapable of withstanding the prolonged fast that a special dispensation was granted. 

Rashi instructed his son-in-law not to extend the fast beyond the one day. The twelfth-century talmudist Rabbi Eliezer ben Joel Ha-Levi (Raviah), after citing a passage from the Jerusalem Talmud about rabbis who fasted on both the ninth and tenth of Av, remarked that such severe mortifications were possible only for the ancient Jews of the holy land who were built of sturdier stuff. ”However in our days the tribulations of exile have rendered us feeble, so that we cannot even observe Yom Kippur for two days.” As evidence for the lethal hazards of excessive fasting he cited a story in the Jerusalem Talmud about the father of Rav Samuel son of Rav Isaac whose intestine split after a two-day Tish’ah be-Av fast, resulting in his death. Still, Rabbi Isaac ben Moses of Vienna counted his teachers Raviah and Rabbi Judah the Pious among those who observed the extra day.

Rabbi Jacob ben Asher wrote in his Arba‘ah Ṭurim code that pious and unusually devout Jews in Germany were still accustomed in his days to keep two days of Yom Kippur. Nor was this stringency confined to one or two fanatics—in some communities there were enough people to make up a proper quorum of ten or more worshippers who assembled as a congregation to conduct the entire festival service—in spite of the vocal protests of Rabbi Jacob’s father, Rabbi Asher ben Jehiel.

Apart from some doubts regarding the status of the International Date Line that beset the refugees of the Mir Yeshiva in Far East in 1941, I am not aware of any recent Jewish sects who have opted for keeping a second day of Yom Kippur. 

During the concluding moments of the solemn day, when our cravings can make us impatient to rush through the prayers and get to the dinner table, it might be worthwhile to remember the fervor of those Jews in former generations who chose to transcend their physical comfort in their quests for spiritual and moral improvement.


  • First Publication:
    • The Jewish Free Press, Calgary, September 6, 2013, p. 19.
  • For further reading:
    • Grossman, Avraham. The Early Sages of Ashkenaz: Their Lives, Leadership and Works (900-1096). Jerusalem: Magnes Press, 1981. 
    • Kanarfogel, Ephraim. Peering Through the Lattices: Mystical, Magical, and Pietistic Dimensions in the Tosafist Period. Detroit: Wayne State University Press, 2000. 
    • Lewin, Benjamin Manasseh. “Teshuvat Rav Hai Ga’on Z”L ‘al devar Shenei Yamim Ṭovim ShellaGaluyyot UT’shuvat Rabbenu Yosef.” Ginzei Ḳedem 4 (1930): 33–37. 
    • Marmorstein, Arthur. Teshuvot ha-geʹonim. Edited by Chaim Leib Ehrenreich. Deva: Oṣar ha-Ḥayyim, 1928. 
    • Stern, Sacha. Calendar and Community: A History of the Jewish Calendar, Second Century BCE-Tenth Century CE. Oxford and New York: Oxford University Press, 2001. 
    • Ta-Shma, Israel M. Halachic Residue in the Zohar. Expanded ed. Sifriyat Helal Ben-Ḥayyim. Tel Aviv: Hakibbutz Hameuchad, 2001.

My email address is: [email protected]

Prof. Eliezer Segal

This article is included in the collection: A Time for Every Purposes, the Alberta Judaic Library, 2015