Rosh Hashanah, Chapter 4, Mishnah 4. This mishnah continues the discussion of the enactments of Rabban Yochanan ben Zakkai that we dealt with in the previous mishnah, except that this enactment relates directly to Rosh Hashanah and to the sanctification of the month - the declaration of the new month.
Accepting testimony about the new month all day long:
"Barishonah hayu mekablin edus hachodesh kol hayom" - originally they would accept the testimony of the witnesses about the new month, including for the purposes of Rosh Hashanah, throughout the entire day. On the thirtieth of Elul, a day that has the potential to become Rosh Hashanah, they would begin the day on the assumption that it would become Rosh Hashanah from the moment the witnesses arrived, and therefore they would accept them all day long.
The incident that led to the enactment:
"Pa'am achas nishtahu ha'edim lavo veniskalkelu haleviyim bashir" - the witnesses were delayed in coming, and the Levites, who would recite the song at the time the afternoon tamid offering was brought, became confused in the song.
To understand this mishap, we must first note that a song was recited at the morning tamid as well. Since the witnesses do not usually arrive at such an early hour, they arranged matters as follows:
At the morning tamid: they recited the weekday song, the regular song of ordinary days, and not the song of Rosh Hashanah.
At the afternoon tamid: they recited the song of Rosh Hashanah, since by the time it was offered the witnesses had generally already arrived.
In that incident the witnesses did not arrive, and the Levites did not know how to proceed. The Gemara records a disagreement about what they did:
According to one opinion, they recited no song at all.
According to the second opinion, they recited the weekday song.
Afterward the witnesses arrived, and the court wanted to sanctify that day as Rosh Hashanah - but the wrong song had already been recited, or no song had been recited at all.
The enactment: accepting witnesses only until minchah:
Following this incident the court enacted "shelo yehu mekablin ela ad haminchah" - that they would accept the witnesses only until the time of minchah, which is the time when the afternoon tamid was offered.
"Im ba'u edim min haminchah ulema'alah - nohagin oso hayom kodesh ulemachar kodesh" - if the witnesses arrived after minchah, they continue to observe the sanctity of Rosh Hashanah on that day, even though it is already known that since their testimony is not accepted the true Rosh Hashanah will fall on the following day; and the next day is observed as sacred as well.
They do not stop observing the sanctity of Rosh Hashanah in the middle of the day, for if they did, people would say the following year: "We observed Rosh Hashanah for nothing, and in the middle of the day we stopped." Therefore they complete that day as the first day of Rosh Hashanah, even though the true Rosh Hashanah is the following day.
The mishnah continues: once the Beis Hamikdash was destroyed, Rabban Yochanan ben Zakkai enacted that testimony about the new month be accepted all day long as it had been originally, since from that time on there is no longer any concern about a mishap with the song.
The Gemara in Maseches Beitzah explains that this enactment of Rabban Yochanan ben Zakkai, to accept the witnesses even at a late hour of the day, was stated only regarding the establishment of the new month. He did not, however, annul the practice that if the witnesses came late, two days of Rosh Hashanah are observed: he accepts their testimony and establishes that day as the first of Tishrei, and nevertheless the sanctity of Rosh Hashanah is observed on the second day as well, in a case where they came late.
A further enactment: the place where the court convenes:
The mishnah goes on to bring another enactment: even if the head of the court - upon whose authority the setting of the date of Rosh Hashanah depends - is somewhere else, outside the place where the Sanhedrin usually convenes, and even if the public knows where he is staying, they do not go to him. Rabban Yochanan ben Zakkai enacted that they always go to the place where the court usually convenes, and there they can sanctify the month when necessary even without his presence.