Why Jews Fast

Fasting in Judaism is perceived as a calendrical event, specifically with Yom Kippur and Tisha be’Av, and several minor fasts, mostly associated with the destruction of the Temple. We rarely, if ever, hear of a community fasting on some other day, and it is almost unheard of to for individuals to observe a personal fast day. A look at the biblical and Second Temple material, however, shows that our current norms are the exact inverse of those in ancient times.

Dr. Rabbi Zev Farber and Dr. Malka Z. Simkovich

Tobit and his wife. Attributed to Rembrandt 1659

Part 1 
Calendrical Fast Days in the Bible

Yom Kippur – The Day of Affliction
The Torah never explicitly describes the most famous Jewish fast day as a day of fasting!   Lev 16:29-34 reads:

Yom Kippur is referenced two other times in the Torah, once as the day of when the Jubilee as declared (Lev 25:9), and once to describe its sacrifices (Num 29:7-11). This latter reference contains the same phrase highlighted above:

The Bible contains no other references to Yom Kippur,^[1] and thus the precise practices implied by the phrase “self-affliction” remain uncertain. Second Temple tradition, rabbinic tradition, as well as Karaite and Samaritan tradition, however, all interpret the Torah’s reference to self-affliction to be a reference to fasting. That fasting is meant by, or included in affliction may be adduced by looking at other biblical verses where the term fasting and self-affliction are used in parallel, especially Isaiah 38:3:

Mourning – The Four Fasts over the Destruction of Judah
The only public, calendrical fast days referenced in the Bible as such are the four days of mourning for the Temple in Zechariah:

The verse seems to imply an inversion, where in the future these days will be a “happy festival,” implying that in the prophet’s time they were days of mourning.^[3]

Part 2
Fasting as a Mourning Practice

Fasting in the Bible is often described or prescribed in reaction to a harsh decree; this may be supplemented by other practices that typify mourning, such as wearing sackcloth, crying, weeping, and putting ashes on one’s head.

Communal Fasting for Harsh decrees
The best-known example of this is the reaction of the Persian Jews to Haman’s decree:

Daniel similarly combines fasting with sackcloth and ashes as part of his turning to God to pray for mercy for the Jews suffering through a long exile:

When a catastrophic pestilence of locusts strikes, causing widespread famine, and the priests are unable to bring offerings to God, the prophet, Joel, understood by most scholars to be a Second Temple book, instructs the people to fast and cry out to YHWH;  he too prescribes other mourning rituals:^[4]

The connection between fasting and mourning is also found in the relatively late book of First Maccabees (2^nd cent. B.C.E.), which describes the reaction of Judah and his followers to the desolation of Jerusalem under Antiochus IV Epiphanes (the Chanukah story):

⁴⁶ Then they gathered together and went to Mizpah, opposite Jerusalem, because Israel formerly had a place of prayer in Mizpah. ⁴⁷ They fasted that day, put on sackcloth and sprinkled ashes on their heads, and tore their clothes (NRSV). ^[5]

This final example shows that mourning was not simply an expression of sadness but a public statement to God, hoping to convince God to help. Strikingly, none of these passages mentions teshuvah, repentance.  

PART 3
Fasting as Supplication: Changing God’s Mind

Although fasting characterized mourning, it was also used as part of a strategy to placate God or convince God to change a decree. (This aspect of fasting is especially relevant for Yom Kippur.)

Reaction to Defeat or Calamity
One frequent use of public mourning appears to have been in reaction to specific calamities: ^[6]  

Fasting to thwart Nebuchadnezzar: Book of Judith
The Second Temple book of Judith (ca. 2^nd century B.C.E.), which purports to tell the story of how Nebuchadnezzar, King of Assyria, sent his general Holofernes to attack Judah, and how the attack was thwarted by the righteous Judith, illustrates this as well. When the people learn that Holofernes will attack imminently, they proceed to set up for a defense, and break out into a massive mourning ritual replete with fasting (Judith Chapter 4):

⁹ And every man of Israel cried out to God with great fervor, and they humbled themselves with much fasting. ¹⁰ They and their wives and their children and their cattle and every resident alien and hired laborer and purchased slave– they all put sackcloth around their waists. ¹¹ And all the Israelite men, women, and children living at Jerusalem prostrated themselves before the temple and put ashes on their heads and spread out their sackcloth before the Lord. ¹² They even draped the altar with sackcloth and cried out in unison, praying fervently to the God of Israel not to allow their infants to be carried off and their wives to be taken as booty, and the towns they had inherited to be destroyed, and the sanctuary to be profaned and desecrated to the malicious joy of the Gentiles.¹³ The Lord heard their prayers and had regard for their distress; for the people fasted many days throughout Judea and in Jerusalem before the sanctuary of the Lord Almighty (NRSV).

The text here explicitly states that God hears their prayers because they fasted for many days.

Fasting in Preparation for a Battle
Fasting was also practiced before battle. For example, Saul forbids his troop from eating, ostensibly to arouse God’s sympathy and give him an advantage in battle (1 Sam 14).

2 Maccabees 13:12 describes a similar practice at a later period (2^nd cent. B.C.E.):

¹² When they had all joined in the same petition and had implored the merciful Lord with weeping and fasting and lying prostrate for three days without ceasing, Judas exhorted them and ordered them to stand ready (NRSV).

The underlying assumption is that God will see his people’s pathetic state and come to their aid.^[7]

A Preventive Measure
Similar practices were also used to avert danger.  For example, Ezra declares a public fast to convince God to protect him and his followers on a journey:

Changing God’s Mind
Isaiah 58 offers the clearest example that people in ancient Israel believed that public expressions of mourning, including fasting, could positively change God’s mind. This chapter argues against this view, stating that fasting alone, without proper ethical behavior is pointless:

Jeremiah 14, in which God tells Jeremiah that he will reject repentance out of hand, similarly notes that fasting is ineffective:

The negative attitude here is different than in Isaiah, since in this case the decree is irreversible and therefore, nothing helps; the Judahites cannot change God’s mind.

The negative attitude toward fasting is a minority opinion in the prophets; Joel’s attitude is much more typical:^[8]

Personal Fasting to Change the Decree:
King David and his Infant

Fasting and mourning to change God’s mind is not only used to avert communal disaster.  For example, King David fasts after the prophet Nathan pronounces God’s the death of his newborn baby, as punishment for his sins of adultery and murder (2 Sam 12):

David fasts for an entire week, until the child dies:

In his servant’s eyes, David’s behavior is backwards, since he mourns his living son but stops upon the infant’s death. Nevertheless, David is explicit that he wasn’t mourning for mourning’s sake, but was trying to change God’s mind by fasting and crying.

Part 4
The Beginnings of Piety:
Late Second Temple Period Practice

None of the previous texts reflect the practice of fasting as reflecting a general practice of piety (i.e., to demonstrate a person’s righteousness), which developed in the Second Temple period.

Tobit – Fasting as an Act of Piety
In the book of Tobit, ^[9] an adventure tale usually dated by scholars to the third or second century BCE, Tobit tells his children on his deathbed that “Prayer with fasting is good, but better than both is almsgiving with righteousness” (Tobit 12:8; NRSV). Tobit’s statement that “prayer with fasting is good,” is wisdom style advice on proper living. This fasting is voluntary, individual, and an expression of piety, like the amount of charity an individual gives.

Judith: The Woman who Fasted Almost Every Day
The book of Judith offers a particularly extreme model of pious fasting.

⁴ Judith remained as a widow for three years and four months ⁵ at home where she set up a tent for herself on the roof of her house. She put sackcloth around her waist and dressed in widow’s clothing. She fasted all the days of her widowhood, except the day before the sabbath and the sabbath itself, the day before the new moon and the day of the new moon, and the festivals and days of rejoicing of the house of Israel (Judith 8:6; NRSV).

Judith’s fasting is voluntary, and expresses her extreme personal piety.

Gospel of Matthew: Debating the Merits of Fasting
The Gospel of Matthew in the New Testament offers another attestation to growth of the “pious fasting” movement.  In Matthew 9:14-16, Jesus debates the merits of fasting with the disciples of John the Baptist:

Then the disciples of John came to him, saying, ‘Why do we and the Pharisees fast often, but your disciples do not fast?’ And Jesus said to them, ‘The wedding-guests cannot mourn as long as the bridegroom is with them, can they? The days will come when the bridegroom is taken away from them, and then they will fast.’ (NRSV) 

This passage implies that the disciples of John and the Pharisees fast often. The word “often” suggests that these fasts are not tied to calendrical dates or past events, but are (spontaneous or regular) acts of piety. John’s disciples want to know why Jesus’s disciples do not display similar acts of piety.

Jesus’ answer presumes that fasting is an act of mourning rather than piety. He predicts that one day, his disciples will lose their beloved—this is a reference to his own imminent death at the hands of the Romans—and when that happens, Jesus’s disciples will have reason to fast. Their fasting will function as acts of mourning, not of piety.

Reading this passage together with Jesus’ statement about fasting in the Sermon on the Mount is especially telling (Matthew 6):

¹⁶ And whenever you fast, do not look dismal, like the hypocrites, for they disfigure their faces so as to show others that they are fasting. Truly I tell you, they have received their reward.  ¹⁷ But when you fast, put oil on your head and wash your face, ¹⁸ so that your fasting may be seen not by others but by your Father who is in secret; and your Father who sees in secret will reward you (NRSV).

This passage suggests that Jesus, like the Pharisees and the disciples of John, believes in fasting for piety, but that such behavior should be done secretly and without fanfare. Reading these texts together suggests that Jesus’ gripe with the disciplines of John was that they made their fasting known and public, and Jesus saw this as hypocrisy. Despite this, fasting gained prominence in Christian circles and emerged as an act that reflected personal piety. In addition, many ascetic Christian communities arose that encouraged its members to avoid sex, food, and other physical indulgences that distract from leading a purely spiritual life.

Part 5
A Survey of Medieval and Premodern
Jewish Fasting Practices

The Mishnah and, consequently, both Talmuds have an entire tractate dedicated to fasting; its main focus is on a series of fasts that Jews of Israel are supposed to hold if rain fails to fall during the winter. This tractate also discusses a host of reasons for personal fasts, including fasts that take up only part of the day, called תענית שעות (a fast of hours).

Medieval times saw the introduction of a sixth fast day, the Fast of Esther, which is kept on the day before Purim, and a seventh, the fast of the firstborn, which is (ostensibly) kept on the day before Pesach. (We say “ostensibly” because no one actually keeps it; instead the custom has become to finish a tractate of Talmud or a seder of Mishnah called a siyyum, and have a festive meal which would exempt the firstborn male from fasting.)

Medieval sources also mention many other fast days. For hundreds of years the Ashkenazi Jewish communities kept something called ב-ה-ב, meaning 2-5-2, a reference to fasting on the second fifth and second days of the week (Monday, Thursday, Monday) after each of the three main Jewish festivals.  These were instituted to repent for whatever excessive levity with which they may have behaved during the holidays. Although virtually no one fasts on these days now, many siddurim (Artscroll, Kol Peh) still have the selichot prayers for these days.

Yahrzeits
The Talmud assumes that a person will fast on the Yahrzeit of a parent.^[10] In medieval Ashkenaz, this was codified as a mitzvah.^[11] This, like the fast of the firstborn, was eventually replaced with a festive Kiddush, this time in honor of the deceased. Extremely pious individuals also fasted on righteous people’s Yahrzeits.^[12] The Shulchan Aruch even suggests that a pious person should fast every single Monday and Thursday, in remembrance of past Jewish tragedies.^[13]   

Kabbalistic Fasting
A kabbalistic practice that began in medieval Ashkenaz where a man would afflict himself with fasting as well as some form of self-punishment, like self-flagellation, exposure to ice, etc.  This was called תשובת המשקל, “the weighty repentance.” For example, in the Rokeach (Laws of Repentance, 6) of R. Elazar of Worms (1176-1238), the reader is told that if he wishes to perform תשובת המשקל for sexual sins, he must fast for at least 40 days, in addition to some other relatively light forms of self-affliction (no meat and wine the night before a fast, uncomfortable bed). 

Fasting for Bad Dreams
Perhaps the most interesting or colorful of the personal fasts is called the תענית חלום, the fast over a (bad) dream, namely a nightmare, aimed at averting the decree that the nightmare presages. The Rabbis wax enthusiastic about this fast, saying “A fast for a nightmare works as efficaciously as fire on a piece of paper ^[14](יפה תענית לחלום כאש לנעורת).” Like the ב-ה-ב fasts described above, this relatively obscure halacha leaves its mark in the liturgy (just look in your Machzorim during the Birkat Kohanim of the high holidays).  

Conclusion – Why We Fast Now

Jewish tradition offers a number of reasons for communal and personal fasting,:

1.  Atonement (Yom Kippur, תשובת המשקל)
2.  Mourning (Temple fasts, Yahrzeits)^[15]
3.  Supplication/Prayer (rain fasts, dream fasts, fasts to avoid evil decrees)
4.  Piety (ב-ה-ב, random personal fasts)

Despite the robust attestation in biblical, rabbinic, and halachic literature of the benefit of fasting as a sign of mourning or repentance, most of these practices are virtually unknown in contemporary Judaism, and have been replaced with siyyums, yahrzeit kiddushes, and Tehillim groups. This gives rise to the popular perception Jews rarely fast, and that fasting in Judaism is simply something we do on fast days.

___________________

Rabbi Dr. Zev Farber is a fellow at Project TABS – TheTorah.com. He holds an M.A. from Hebrew University in Jewish History (biblical period) and a Ph.D. from Emory University in Jewish Religious Cultures. In addition to academic training, Zev holds ordination (yoreh yoreh) and advanced ordination (yadin yadin) from Yeshivat Chovevei Torah (YCT) Rabbinical School. Zev’s edited volumes on brain death and organ donation are forthcoming from Koren and his book on Joshua in reception history is forthcoming in De Gruyter’s BZAW series. 

Dr Malka Simkovich has a Ph.D. in Second Temple Judaism from Brandeis University. She earned an MA degree in Hebrew Bible from Harvard University and a BA in Bible Studies and Music Theory from Stern College of Yeshiva University. Malka is a visiting Professor of Jewish Studies at Catholic Theological Union in Chicago, and works as an editorial assistant for the Harvard Theological Review 

[1] See the TABS essays, “The Absence of Yom Kippur in Nevi’im and Ketuvim,” and “Does Ezekiel in 572 B.C.E. Know of Yom Kippur,” for more discussion of this.  

[2] Arguing that fasting is the plain meaning of the Yom Kippur text in Leviticus, Amos Hacham uses this argument together with a point about the term נפש, which in old Hebrew refers to the throat (not the soul). “Afflicting the throat,” he argues, would be a decent depiction of fasting; see for example Psalms 107:20, where we find the expression “hunger of the throat/spirit (נפש רעבה).”  Amos Hacham, “Fasting in the Bible,” Machanaim 82 (5723), accessible online at Daat.

[3] Another example would be the reaction of the inhabitants of Jabesh-Gilead to the death of Saul and his sons in 1 Chronicles 10:12.

[4] Similarly in Nehemiah 9:1-2, the Jews observe a fast and express their mourning over the fact that they sinned by intermarriage.

[5] That the Temple was considered the proper place for such a ritual explains why the author felt the need to explain why Judah held this ritual somewhere else.

[6] An example of an individual who reacts to a calamity with fasting is Nehemiah, who does so upon hearing of the terrible state of Jerusalem (Neh 1:4).  

[7] Judah’s three day fast recalls that of Esther, which was in preparation not for war but for speaking with Ahasueros (Esther 4):

Unlike in 2 Maccabees, since God is never mentioned in the Masoretic text of Esther, the function of this fast—other than solidarity—remains implied but never stated.

[8] Other examples of public fasts in the Bible are Jer 36:9 and 1 Kings 21:9; neither of these texts make it clear what the purpose of said fast had been. These texts do suggest that declarations of public fast days were relatively common.

[9]  For more on Tobit see Malka Simkovich’s TABS essay, “The Book of Tobit.”

[10] This can be seen in passages in which an oath against eating something is made with the language “this meat/wine/etc. is to me like it is on the day on which my father/mother died.”

[11] See Kol Bo 114 in the name of Rabbi Meir of Rothenberg, referenced by Remah in Shulchan Aruch, Yoreh Deah 402:12.

[12] See the list that appears as an addendum to the Megillat Taanit  of days we should fast, and those we should not. The list still appears in the Shulchan Aruch (Orach Chayim, Laws of Fasting, 580:2).

[13] Orach Chayim, Laws of Fasting, 580:3

יש מי שאומר שגזרו שיהיו מתענין בכל שני וחמישי על חורבן הבית, ועל התורה שנשרפה, ועל חלול השם; ולעתיד לבוא יהפכם ה’ לששון ולשמחה.

[14] Gen Rab, “Lech Lecha” 42:12; b. Taanit 12b; b. Shabbat 11a; Pesikta deRav Kahana 21, etc.

[15] Interestingly, we are aware of no evidence that fasting was ever part of standard mourning for the deceased, at least during the rabbinic period and on, despite the fact that it appears in the Bible as a mourning practice.