- Shabbat and Holidays
- Rosh Chodesh
Rosh Ĥodesh is one of the holidays on which it is appropriate to rejoice. However, there is no explicit commandment to rejoice on Rosh Ĥodesh by conducting festive meals. Therefore, while it is meritorious to enjoy special meals on Rosh Ĥodesh, one is not obligated to do so (sa 419:1).
Nevertheless, one may not grieve on Rosh Ĥodesh, and therefore one may not fast on the day (ibid. 418:1). Anyone who refrains from eating on Rosh Ĥodesh, even for a short period of time, with the intention of fasting, transgresses this prohibition. But if, by chance, one neglected to eat for several hours, there is no reason for concern (bhl 418, s.v. "Rosh Ĥodesh assur"; Kaf Ha-ĥayim 418:3). Technically, one who ate only fruits on Rosh Ĥodesh is not considered one who has fasted and thus transgressed; rather, he simply failed to fulfill the mitzva of enjoying festive meals on Rosh Ĥodesh.
The main way to fulfill this mitzva is by adding a special dish to one’s regular menu in honor of Rosh Ĥodesh. This mitzva applies even when Rosh Ĥodesh coincides with Shabbat (mb 418:2, 419:1-2).
Even though one is not obligated to eat bread at a Rosh Ĥodesh meal, it is a mitzva to do so (sht 419:1).
It is proper to set the table respectfully for a Rosh Ĥodesh meal. Some are meticulous about eating meat and drinking wine at a Rosh Ĥodesh meal.
When Rosh Ĥodesh lasts two days, there is a mitzva to prepare festive meals on both days. The primary mitzva is to conduct these meals during the day, but some say that there is a mitzva to conduct festive meals at night as well, in honor of Rosh Ĥodesh.
One may not do things on Rosh Ĥodesh that evoke sorrow. Therefore, one may not deliver a eulogy on Rosh Ĥodesh. If, however, the deceased was a Torah scholar, one may deliver a eulogy, but only in the presence of the body (sa 420:1, mb ad loc. 1; yd 401:5).
Similarly, it is customary to refrain from visiting cemeteries on Rosh Ĥodesh. Therefore, if the yahrzeit (anniversary of death) or the end of shloshim (the first thirty days after death) coincides with Rosh Ĥodesh, the friends and relatives of the deceased should visit the grave on the day before Rosh Ĥodesh. If that is impossible, they should go after Rosh Ĥodesh. One may visit kivrei tzadikim (graves of righteous people) on Rosh Ĥodesh because this does not evoke sorrow.
A bride and groom who follow the custom of fasting on their wedding day (an Ashkenazic custom that some Sephardim also follow) should not fast if their wedding takes place on Rosh Ĥodesh (sa 573:1).
 Rashi states in Ta’anit 15b, "Even though it is called mo’ed, the Torah does not call it a day of feasting and joy." Rosh (Ber. 7:23) concurs, stating that we do not insert the word simĥa (joy) into the corrective berakha for Birkat Ha-mazon on Rosh Ĥodesh (see below n. 14). In contrast, Yerei’im 227 states, "One is obligated to rejoice on Rosh Ĥodesh," though there is no obligation to eat bread at the meal, because one can satisfy the requirement of joy by eating meat and drinking wine. The final halakha remains as stated above.
Rambam maintains that fasting on Rosh Ĥodesh is prohibited by Torah law, while Beit Yosef 418 maintains that it is rabbinically prohibited. There was a custom among the ĥasidim rishonim (pious people of yore) to fast on two particular Rosh Ĥodesh days – the first of Nisan, because Aharon’s sons died on that date, and the first of Av, because Aharon himself died on that date (sa 580:2). Rema 580:1 comments that one should not fast on Rosh Ĥodesh for the entire day; rather he should eat before nightfall. A regular person should not accept upon himself to fast on these days of Rosh Ĥodesh.
 The custom to beautify the mitzva by setting the table respectfully is cited in Ben Ish Ĥai, Year 2, Vayikra 10 and Kaf Ha-ĥayim 419:5. Eating meat and drinking wine are also ways to beautify the mitzva in honor of Rosh Ĥodesh. According to Yerei’im, however, it is an actual mitzva, as mentioned in the previous note. This is why most Sephardic Jews only begin to refrain from eating meat and drinking wine from the second of Av, in order to uphold the honor of Rosh Ĥodesh. The Ashkenazic custom is to refrain from meat and wine on Rosh Ĥodesh Av as well (see below 8:13).
mb 419:2 states that there is no need to conduct a festive meal on Rosh Ĥodesh night, but Responsa Rema Mi-Fano §79 and Eshel Avraham (Buczacz) maintain that there is a mitzva to do so.
 According to Rema 573:1 and mb 573:9, they should fast on Rosh Ĥodesh Nisan, because there is a minhag ĥasidim (practice of the pious) to fast on that day anyway. Pri Megadim maintains that one who does not usually fast on Rosh Ĥodesh Nisan should not do so on his or her wedding day. See Sefer Rosh Ĥodesh 14:19 and n. 39, where the author discusses the case of a wedding that takes place on the first night of Rosh Ĥodesh when the bride and groom surely fast during the day prior to the wedding. He explains that according to ahs EH 61:21, who maintains that brides and grooms fast in order to ensure that they are not drunk at their wedding, they should continue fasting until after they exit the ĥupa (ritual wedding canopy), even though this will mean that they are entering Rosh Ĥodesh in an afflicted state. Kitzur sa 146:1, on the other hand, maintains that brides and grooms always fast only until nightfall even if this occurs before the ĥupa, because the purpose of the fast is atonement.