From what I understand, fasting is for the purpose of self-affliction and repentance. Can a person hold his or her own personal fast, in addition to the mandatory public fast days? If yes, are there special repentance prayers one can say on such a day?


Historically, personal fasting has always been considered an accepted, indeed an optimal, method of repentance. It may be observed in times of personal or communal calamity in order to elicit divine mercy, or, more commonly, as penitence for personal wrongdoing.1 In times past it was very common for people to regularly designate personal atonement fasts.

The Talmud explains that fasting is in lieu of the sacrifice that one would bring following a sin – in the times that the Holy Temple stood in Jerusalem – in order to return to G‑d's good graces. As our Sages say, "May it be His will that He should consider the fat and blood reduced [by the fast] as if I offered it upon the Altar."2

(For more about what is accomplished by fasting, see My Body and I. Though the article talks about Yom Kippur, the ideas therein apply to all fast days, personal and communal.)

Personal fasts last from dawn until nightfall.3

In anticipation of a personal fast, it should be verbally accepted in advance. This is normally done during the afternoon prayers of the preceding day. Towards the conclusion of the Amidah, immediately before saying the passage of Elohai Netzor say: Hareini b'taanit yachid l'machar ("I will be observing a personal fast-day tomorrow").4

On the fast day itself, there is a special prayer, Aneinu, which is added to the Shema Koleinu blessing of the afternoon Amidah. It can be found in your prayer book.

I should note that personal fasts are not very common anymore. Rabbi Schneur Zalman of Liadi (the Alter Rebbe) writes in the third chapter of Igeret HaTeshuvah that fasting – with the exception of mandatory public fast days – must never come at the expense of one’s health or strength. If fasting will weaken you to the extent that you will not be able to serve G‑d that day with the same energy and vigor as you would have had you eaten—don’t. In fact, the Talmud is very clear about this: One who fasts despite the fact that it weakens him, is called a sinner.5

In today's day and age, when most of us are used to eating three round meals a day, there is almost no one who can claim to be unaffected by fasting.6

More importantly, it is the spirit of repentance, the true repentance, that comes along with fasting that counts.

So if we don't fast, is there another way to gain comparable atonement?

Yes. In the words of Daniel, when advising Nebuchadnezzar: "Redeem your sins with charity, and your wrongdoing by being kind to the needy."7

This can be done by donating to a charitable cause the monetary value of the food you eat on a given day.

"Therefore, all who revere the word of G‑d are now accustomed to being unstintingly generous with charity, which is given in place of fasting, for the prevalent lack of strength prevents them from [fasting]."8

I hope this helps.

Rabbi Eliezer Zalmanov