1) THE JEWS BOWED DURING VIDUY IN THE BEIS HA'MIKDASH
QUESTION: Rav Yehudah says in the name of Rav that a miracle occurred when the multitudes of Jews crowded into the Beis ha'Mikdash during the festivals. When they stood in the Azarah they were crowded, but when they bowed down they had plenty of room ("Omdin Tzefufin u'Mishtachavim Revachim"). The Gemara says that this is one of the ten miracles which occurred in the Beis ha'Mikdash, as enumerated in Avos (5:5).
RASHI writes that they bowed for Viduy, the confession of sins which is part of the procedure of Teshuvah. The miracle was that when each person bowed down to recite Viduy, he had plenty of room and no one was near him to hear his confession.
However, Viduy is not recited on any of the festivals (with the exception of Yom Kippur). What does Rashi mean when he says that they bowed for Viduy?
(a) The TASHBETZ (3:37) asserts that this miracle occurred only on Yom Kippur. Yom Kippur is the only Yom Tov for which Viduy is said as part of the Avodah in the Beis ha'Mikdash. He says this is also the intent of Rashi here.
The SI'ACH YITZCHAK agrees with the Tashbetz that when Rashi here says that they bowed during Viduy, he refers specifically to Yom Kippur.
(b) It is possible that when RASHI says that the people bowed during Viduy, he refers not to the ordinary Viduy but to their request during Tefilah for Mechilah, forgiveness. When the people ascended to Yerushalayim for the festival and entered the Beis ha'Mikdash, they would pray to Hash-m and request their needs. The people took advantage of the opportunity of being in the presence of the Shechinah to ask Hash-m for all of their needs, and their prayers included requests for Mechilah as well. At the point in the prayers at which they asked for forgiveness for their sins, they enumerated their sins (Viduy).
When Rashi in Avos (5:5) explains the miracle as it is recorded there, he writes that when each person bowed, he had plenty of room and no one was near him "to hear his prayer." This is also the way the Midrash (Bereishis Rabah 5:7) explains the miracle. This supports the contention that the Viduy that Rashi mentions here was merely part of the prayers that were said when the people came to the Beis ha'Mikdash.
Although the Halachah disapproves of reciting Viduy on Shabbos and Yom Tov, one certainly is permitted to recite Viduy when there is a need to do so specifically on that day, as the BE'ER HEITEV (OC 288:3) writes. The moment that one stands in the Azarah of the Beis ha'Mikdash on Yom Tov in the presence of the Shechinah is an opportune time to confess one's sins and ask for forgiveness.
The MACHATZIS HA'SHEKEL (OC 288:13) cites the ROSH who says that the people may recite the Thirteen Attributes of Mercy (Midos Rachamim) even on Shabbos when there is a need to supplicate for rain. The MAGEN AVRAHAM there permits even Nefilas Apayim, falling on one's arm (as one does for Tachanun), on Shabbos. The Gemara here, according to Rashi's explanation, is strong support for his ruling.
(The KISVEI HA'GRIZ explains that the Gemara here refers to when the people bowed upon their entry into the Azarah. Anyone who enters the Azarah must bow, as derived from the Parshah of Bikurim, as the VILNA GA'ON writes in Aderes Eliyahu, Parshas Ki Savo.)
2) AGADAH: "THEY STOOD CROWDED, BUT THEY BOWED WITH SPACE"
Rav Yehudah says in the name of Rav that a miracle occurred when the multitudes of Jews crowded into the Beis ha'Mikdash during the three festivals. When they stood in the Azarah they were crowded, but when they bowed down they had plenty of room ("Omdin Tzefufin u'Mishtachavim Revachim"). The Gemara says that this is one of the ten miracles which occurred in the Beis ha'Mikdash, as enumerated in Avos (5:5).
RAV YONASAN EIBESHITZ (in Ahavas Yonasan, cited by Einei Shmuel) explains this miracle as follows. The Gemara in Berachos (6a), in its discussion about Shedim ("demons," or forces that inflict harm), relates that during the public lecture held prior to the festivals, when many people gathered to learn the Halachos of the upcoming festival, the feeling of crowdedness that they experienced was due to the presence of Shedim.
The Gemara in Kidushin (29b) relates that there was a certain Shed which had the appearance of a seven-headed serpent. It resided in a certain study hall and terrorized the people. When Rav Acha bar Yakov entered the study hall and the Shed attacked him, he bowed down to Hash-m in prayer. When he bowed down, one head of the Shed fell off. He bowed seven times until all seven heads of the Shed fell off and the Shed died. This incident teaches that bowing down to Hash-m is one way to destroy Shedim.
The crowded feeling the Jews felt in the Beis ha'Mikdash during the festival was due to the presence of Shedim, like the crowded feeling they felt during the public lecture before the festival. When the people in the Beis ha'Mikdash bowed down to Hash-m, their acceptance of His sovereignty caused the destruction of the Shedim (at least momentarily) and eliminated the crowded feeling.