Shulchan Aruch: Chapter 597 - Whether it is Permitted to Fast on Rosh HaShanah

SECTION 597 Whether it is Permitted to Fast on Rosh HaShanah. (1–9)

1 Certain authorities maintain that it is a mitzvah to fast on Rosh HaShanah and on Shabbos Shuvah as on all of the Ten Days of Repentance. The halachah, however, does not follow their opinion; it is forbidden to fast on Rosh HaShanah and Shabbos Shuvah, just as it is forbidden to fast on any other Shabbos or festival.1 Even if one has a disturbing dream, but is in doubt as to whether it is one of the dreams that would require him to fast on Shabbos,2 he should not fast. On the contrary, it is a mitzvah for him to eat, drink, and rejoice on Rosh HaShanah, as stated in sec. 581.3 Nevertheless, people should not eat to the point of satiety, so that they do not become frivolous, and so that the fear of G‑d will be upon them.

2 There is a tradition handed down in certain communities that whoever has established the custom of fasting on Rosh HaShanah, and then deviates from it and does not fast, will not live out that year. Nevertheless, one who is not anxious about his life need not fast throughout his life, though he must annul his commitment in the manner that other vows are annulled.4

3 If a person fasts on Rosh HaShanah, he must study or recite supplications throughout the day. For every festival must be divided, half “for G‑d” and half “for yourselves,”5 in order to fulfill [the charges] found in two verses, one6 [which describes a festival as “an assembly] for G‑d,”7 and the other8 [which refers to it as “an assembly] for yourselves.”9 This person who is fasting and who does not fulfill [the charge to celebrate the festival] “for yourselves” must dedicate the festival totally “for G‑d,” and in that way fulfill the commandment [to hold “an assembly] for G‑d.” [That verse does not mention] “for yourselves,” indicating that [in such a case] the entire day should be [consecrated] to G‑d alone.

4 A person who fasts on Rosh HaShanah or on any other festival is forbidden to cook — or to perform any other labors necessary for the preparation of food — for the benefit of others, as stated in sec. 527[:30]. Note the reason explained there.

5 Some people say that they have received the tradition that a person who fasted once on the first day of Rosh HaShanah because of a [disturbing] dream must fast on both days of Rosh HaShanah throughout his life, even if [one of them] falls on Shabbos. [The rationale:] Since he was once shown an unfavorable sign at the beginning of Rosh HaShanah, on the first night, this indicates that his fasting is cherished by the Holy One, blessed be He, on Rosh HaShanah, and that he should therefore carry out His will and fast both days of Rosh HaShanah, for they are considered as one long day, as explained in sec. 600[:3].

However, [he] is forbidden to fast on the nights of Rosh HaShanah, just as on other festivals, for even in his dream it was indicated only that he should fast during the day, as with all fasts undertaken because of a dream: one fasts only during the day.

6 If he had the [disturbing] dream on the second [night] of Rosh HaShanah, he should fast on the second day of Rosh HaShanah for the rest of his life, but not on the first day.

Nevertheless, whoever is not anxious for his life need not be concerned about this tradition and need not fast at all throughout his life [on Rosh HaShanah], neither on the first day or the second day, even if he had the [disturbing] dream on the first [night].

7 If one fasts on Rosh HaShanah because of a disturbing dream, he does not have to fast again on a weekday to atone for his fast, as is required if one fasts on Shabbos or on another festival, as stated in sec. 288[:3. The rationale is that] there are opinions that it is a mitzvah to fast on Rosh HaShanah.10 Although the halachah does not follow this view, it is of sufficient weight to rely upon so that this fast will not be considered a transgression for which a second fast is required during the week [as atonement].

8 [Ordinarily,] when one undertakes to fast on Shabbos or on a festival, his acceptance of the fast is of no consequence, and he may eat without having [his commitment] annulled, as stated in sec. 570.11 Nevertheless, if one undertakes to fast on Rosh HaShanah, even if he does not make a formal vow, but merely accepts the fast, saying: “I am hereby obligated to fast on Rosh HaShanah,” he must have his commitment annulled.

[The rationale is that] since some authorities maintain that it is a mitzvah to fast [on Rosh HaShanah], [his acceptance of the fast] does not resemble a commitment to perform a transgression, in which instance the commitment is of no consequence.12

9 People who follow the custom of fasting on Rosh HaShanah should not recite the passage beginning Aneinu [in the Afternoon Service], just as we do not recite [it] on Yom Kippur. [The rationale is that] these are days of judgment and it is not appropriate to say [as stated in that passage], “Answer us on our fastday.”13