Unlike the other “minor” fasts, which are enumerated and discussed by the Talmud (Ta'anit 29a), Ta'anit Esther is not mentioned anywhere in the Mishna or Talmud. In fact, the earliest reference to Ta'anit Esther appears in the eighth-century Geonic work Sheiltot de-Rav Achai, authored by R. Achai Gaon. In any event, the fast is discussed by the Rishonim, codified by the Shulchan Arukh (O.C. 686) and universally observed.
What is the source and nature of this fast, and how should we understand its relationship to Purim?
The Shibolei Ha-leket (cited in the Beit Yosef, O.C. 686) cites Rashi as explaining that Ta'anit Esther commemorates the three-day fast observed by the Jews of Shushan at Esther’s behest during the month of Nissan (Megilla 15a), before she approached Achashverosh to invite him to the feast. Recall from the Megilla that Esther told Mordekhai before she approached the king:
Go, gather together all the Jews that are present in Shushan, and fast for me, and neither eat nor drink, for three days, night and day; My maidens and I, too, will fast in like manner; and so will I go in unto the king, which is not according to the law; and if I perish, I perish. (4:16)
Rashi describes this fast as a "mere custom" (minhag be-alma), and criticizes those who treat it with unnecessary stringency.
Rabbeinu Tam, on the other hand, as cited by the Rosh (Megilla 1:1), suggests that Ta'anit Esther is a rabbinic obligation, alluded to by the Talmud (Megilla 2a), and commemorates the day upon which the Jews gathered to fight those who sought to destroy them (the 13th of Adar). The Rosh writes:
“It is a day of gathering for everyone” – that everyone gathers together for the Fast of Esther. The rural population comes to the cities to recite Selichot and supplications, just as on this day the Jews gathered together to defend themselves and thus required Divine mercy. Likewise, we find that Moshe declared a fast when they [Benei Yisrael] fought against Amalek, as it is written, “And Moshe, Aharon and Chur ascended to the top of the mountain” (Shemot 17:10), and Masekhet Ta'anit derives from here that “three [authorities] are required [to declare] a public fast.” Rabbeinu Tam brought proof from here for our observance of Ta'anit Esther, which we commemorate as they did in the days of Mordekhai and Esther, when the Jews gathered to defend themselves. We find no other proof for [the practice of Ta'anit Esther] other than here.
The Ra'avad (cited by the Ran, Ta'anit 7a in the
The thirteenth isn't similar to the other fasts, as it commemorates the miracle which occurred [on that day]. In addition, we have a written reference to it as it says (Esther 9:31): "To confirm these days of Purim in their appointed times, as Mordecai the Jew and Queen Esther had enjoined them, and as they had ordained for themselves and for their seed, the matters of the FASTINGS and their cry…" – in other words, to observe this fast each and every year.
According to the Ra'avad, the fast of Esther was actually instituted as part of the original Purim edict. Our celebration includes reenacting the fast which preceded the war, during which the Jewish people experienced a miraculous redemption. Incidentally, the Rambam (Hilkhot Ta'aniyot 5:5) also identifies this verse as the source for Ta'anit Esther, though he does refer to it as just a “custom.”
We have thus identified three possible sources for this fast, which reflect three different levels of the obligation. Seemingly, the lower the obligation of the fast, the more readily we will permit a person to eat in certain situations. Indeed, the Shulchan Arukh (686:2) states, "This fast is not an obligation; therefore, we may be lenient regarding the fast in cases of need, such as a pregnant or nursing woman or a sick patient."
A second question that arises concerns the nature and character of this fast. While the other fast days express our sorrow over the loss of the Beit Ha-mikdash, it remains unclear whether Ta'anit Esther shares the mournful qualities of the other fasts. Indeed, the Ra'avad cited above describes the fast in almost festive terms.
Rav Soloveitchik, as quoted in Rav Michel Shurkin’s Harerei Kedem (188), notes a number of practical ramifications of this question. For example, would the Rambam’s ruling (Hilkhot Ta'aniyot 1:14) advocating that one refrain from "idunim" (entertainment or physical delights) on fast days apply on Ta'anit Esther? If we place Ta’anit Esther in a separate category from the other fasts, as a festive, rather than mournful, occasion, then we would likely permit such activities. Indeed, the work Piskei Teshuvot (686:2) rules that on Ta’anit Esther one may listen to music and prepare new clothing, activities which are generally discouraged on other fast days.
Furthermore, Rav Soloveitchik suggests that the Rambam's assertion that the fast days will not be observed in the messianic era (Hilkhot Ta'aniyot 5:9) might not apply to Ta'anit Esther, which is an integral part of the Purim celebration (see Rambam, Hilkhot Megilla 2:18).
While questioning the character of the day, one might also explore whether Ta'anit Esther constitutes a separate custom or obligation, or whether it is integrally connected to the observance of Purim.
For example, the Rambam (Hilkhot Megilla 5:5) and Shulchan Arukh (686:2) rule that when Purim falls on Sunday, in which case we cannot fast on the day immediately preceding Purim (Shabbat), we fast on the previous Thursday. The Kolbo (R. Aaron b. Yaakov of Lunel), however, rules (in Siman 45) that one should fast on Friday, so that the fast is juxtaposed to Purim as closely as possible. (See Shibbolei Ha-leket, Purim, 194, who severely criticizes this practice.) Apparently the Kolbo views the fast as an integral part of Purim, which should be observed as close to Purim as possible, even at the price of fasting on Friday, which we generally avoid.
I believe that there is a much deeper question that we must ask, as well, concerning the observance of Ta’anit Esther: In what way, if at all, does Ta’anit Esther contribute to the Purim celebration? Some of the aforementioned sources indicate that while the fast may be commemorative, it is hardly integral to the Purim celebration. Furthermore, a careful look at Ta'anit Esther reveals that it does not, according to some views, accurately commemorate the events portrayed by the Megilla. Moreover, it does not conform to the rules of other fast days, as we demonstrated above! These discrepancies seem to indicate that Ta'anit Esther might not commemorate a tragic event, or any event, at all. Rather, it may simply be another day of Purim, yet one of a different character.
Rav Soloveitchik zt"l (see Days of Deliverance, pp. 1-4) suggested that Purim and Ta'anit Esther commemorate two distinct themes of Purim, which he claimed may be rooted in the different themes of the Megilla itself.
He notes in this context the Gemara’s discussion (Megilla 3b) concerning the requirement to read the Megilla twice, both by night and during the day. The Gemara cites two Scriptural sources for this halakha, two verses in which man is commanded to repeat his call to God. The first source, "My God, I call out to you during the day, but you do not answer, and in the night, as well, I am not silent" (Tehillim 22:3), compares the Megilla reading to a desperate cry for help. The second source, "So that my glory may sing praise to you and not be silent, Hashem, my God, I continuously thank you" (Tehillim 30:13), equates mikra Megilla with a song of praise for God.
Rav Soloveitchik suggested that both themes accurately capture the nature of Purim. During most of the Purim story, the Jewish people are threatened and pursued; the redemption surfaces only towards the end of the Megilla. In other words, the story of Purim, and, subsequently, its celebration, involves two parts: an acknowledgement of the crisis and "what could have been," as well as thanksgiving for the redemption.
Ta'anit Esther and Purim, therefore, reflect two aspects of the Purim celebration. Each, without the other, is incomplete. One cannot truly appreciate Purim without having fasted on Ta'anit Esther, and Ta'anit Esther alone certainly doesn't capture the totality of the Purim story.
Interestingly, the Shibbolei Ha-leket cites R. Amaram Gaon as recording the custom of the Tanna’im and Amora’im, as well as the “house of the courts,” to recite supplications and solemn prayers on Purim day itself! Apparently, this custom attempts to integrate both themes into the day of Purim.
This dialectic, of course, not only portrays the different components of the Purim story, but accurately reflects the precarious existence of the Jewish people since the destruction of the Temples, during which time the story of Purim occurred.