תקצז אם מותר להתענות בראש השנה ובו ט' סעיפים

If It Is Permitted to Fast on Rosh Hashanah

1. There are those who say that it is a mitzvah to fast on Rosh Hashanah and on Shabbos Teshuvah, just as on all the Ten Days of Teshuvah.

But the halachah does not follow their view.

Rather, it is forbidden to fast on Rosh Hashanah and on Shabbos Teshuvah, just as it is forbidden on other Shabbosim and Yomim Tovim.

Even if one saw a bad dream and is unsure whether it is one of the dreams for which one may fast on Shabbos, he should not fast.

And it is a mitzvah to eat, drink, and rejoice on Rosh Hashanah, as stated in siman 581.

However, one should not eat to excess, so that they do not treat the day lightly, and so that the fear of Hashem will be upon them.

2. There are places where it is an accepted tradition that anyone who is accustomed to fasting on Rosh Hashanah, and then changes his custom and does not fast, will not complete his year.

Nevertheless, one who does not fear for his life does not need to fast all his days, but he does need to perform hataras nedarim, as with any other vow.

3. One who fasts on Rosh Hashanah must spend the entire day learning or reciting supplications.

For every Yom Tov must be divided—half for Hashem and half for yourselves—in order to fulfill both verses: one that says "for Hashem," and one that says "for you."

And this person who fasts and does not fulfill the verse that says "for you," must devote the entire day to Hashem.

In order to fulfill the verse that says "for Hashem" and not "for you," which implies that the entire day should be for Hashem alone.

4. One who fasts on Rosh Hashanah or on other Yomim Tovim is forbidden to cook or perform other food-related labors for others, as stated in siman 527. See there for the reason.

5. There are those who have a tradition that if one fasted once on Rosh Hashanah as a fast for a dream, and it was on the first day of Rosh Hashanah, he must fast both days of Rosh Hashanah for the rest of his life, even when it falls on Shabbos.

Since he was shown a bad sign once at the beginning of Rosh Hashanah, on the first night, it was hinted to him that his fast is cherished before the Holy One, blessed be He, on Rosh Hashanah.

Therefore, he should fulfill this will and fast both days of Rosh Hashanah, which are considered as one long day, as stated in siman 600.

But it is forbidden to fast at night on Rosh Hashanah, just as on other Yomim Tovim.

For even in his dream, he was only hinted to fast during the day, as is the case with all fasts for dreams, which are only observed during the day.

6. And if the dream was shown to him on the second day of Rosh Hashanah, he should fast only the second day for the rest of his life, and not the first day.

Nevertheless, one who does not fear for his life does not need to be concerned for this tradition, and does not need to fast all his days at all—not on the first day and not on the second day—even if the dream was on the first day.

7. One who fasts on Rosh Hashanah as a fast for a dream does not need to observe a compensatory fast on a weekday for having fasted, as is required for one who fasts on Shabbos or Yom Tov, as stated in siman 288.

For there are those who say that it is a mitzvah to fast on Rosh Hashanah.

And even though the halachah does not follow their view, nevertheless, it is sufficient to rely on them so that this fast is not considered a transgression that would require a compensatory fast on a weekday.

8. Even though one who accepted upon himself to fast on Shabbos or Yom Tov, his acceptance is not valid, and he may eat without hataras nedarim, as stated in siman 610, nevertheless, one who accepted upon himself to fast on Rosh Hashanah—even if he did not phrase it as a vow, but merely as an acceptance of a fast, saying "I accept upon myself to fast on Rosh Hashanah"—requires hataras nedarim.

Since there are those who say it is a mitzvah to fast, this is not like accepting upon oneself to commit a transgression, which would not require any annulment.

9. Those who are accustomed to fast on Rosh Hashanah should not recite "Aneinu," just as "Aneinu" is not recited on Yom Kippur.

Because these are days of judgment, and it is not appropriate to say "on the day of our fast."