On the holiday of Shavuot, it is a Mitzvah to divide the day into two parts: Half of the day should be spent immersed in Torah study and prayer in the synagogue and Bet Midrash and the other half of the day should be spent eating, drinking, and enjoying one’s self. This is based on the opinion of Rabbi Yehoshua (Betzah 15b) who rules, “Half for Hashem and half for you.”
Just as it is a Mitzvah to honor and enjoy Shabbat, it is likewise a Mitzvah to honor and enjoy the holidays, as the verse states, “To the holy of Hashem-honored!”. Thus, one should not minimize in one’s Yom Tov expenditures, for Hashem exclaims, “My children, borrow on my account and I shall repay you!” Just as one has an additional soul on Shabbat, the same applies on Yom Tov. One must exhibit joy on Yom Tov and for men, an integral part of this joy is partaking of meal consisting meat and wine on Yom Tov. Women, who are not as gladdened by meat and wine as much as men are, should be gladdened by purchasing nice clothing or jewelry for them. Children should be gladdened with candies and other sweets.
In the previous Halacha, we have explained that one must mention “Ya’aleh Ve’Yavo” in the Birkat Hamazon recited on holidays and Rosh Chodesh. We have also discussed the correct procedure for one who remembers in the middle of Birkat Hamazon that one has not inserted “Ya’aleh Ve’Yavo”.
If one becomes aware that one has not recited “Ya’aleh Ve’Yavo” only after having recited the words “La’ad Ha’el Avinu Malkenu”, one can no longer rectify this error and there are certain times where one will be obligated to repeat the entire Birkat Hamazon and other times when one will not.
The rule is: When one is obligated to eat bread in the current meal then reciting “Ya’aleh Ve’Yavo” within Birkat Hamazon of that meal is compulsory and if one has not done so, one must repeat the entire Birkat Hamazon. On the other hand, if eating bread as part of the current meal is not obligatory, such as the case with regards to meals on Rosh Chodesh when, if one has mistakenly omitted “Ya’aleh Ve’Yavo” from Birkat Hamazon, one does not repeat Birkat Hamazon. However, the meals on the first night of Pesach and Sukkot (first two nights outside of Israel), if one forgets to add “Ya’aleh Ve’Yavo”, one must repeat Birkat Hamazon since there is an absolute obligation to eat bread during these meals.
It would therefore seem that if one forgot to insert “Ya’aleh Ve’Yavo” in Birkat Hamazon of the Shavuot holiday meal, since eating bread during this meal is obligatory, one must repeat Birkat Hamazon, as is the law with regards to the first night(s) of Pesach and Sukkot. Nevertheless, Maran Rabbeinu Ovadia Yosef zt”l writes that since the issue of the obligation to eat bread on Shavuot is subject to disagreement, as some Rishonim maintain that if one does not wish to eat bread on Shavuot, one need not, for the only explicit Torah commandment to eat bread is on the first night of Pesach and the first night of Sukkot; however, on Shavuot there is no such obligation. Thus, although we follow the ruling of the Rambam and Rosh that there is indeed an obligation to eat bread on Shavuot as well, nevertheless, regarding the repetition of Birkat Hamazon, we follow the rule that “when in doubt, do not bless,” meaning that due to the severity of the prohibition of uttering a blessing in vain, as long as a disagreement exists whether or not one must recite the blessing again, one should not repeat the blessing.
Although, in general, regarding Birkat Hamazon we do not follow the rule of “when in doubt, do not bless” since reciting Birkat Hamazon is a Torah obligation and regarding such things, we have another general rule which states “regarding a doubt pertaining to a Torah law, one must act stringently” (as we have explained regarding the law of one who is in doubt regarding whether or not one has recited Birkat Hamazon), nevertheless, since mentioning “Ya’aleh Ve’Yavo” in Birkat Hamazon is only a rabbinic enactment, when a dispute or doubt exists whether or not one must repeat Birkat Hamazon due to the omission of “Ya’aleh Ve’Yavo”, we follow the original rule of “when in doubt, do not bless.”
Summary: If one has mistakenly omitted “Ya’aleh Ve’Yavo” from Birkat Hamazon on Shavuot, one should not repeat Birkat Hamazon.
