- The status of an egg laid on the first day of Rosh Hashanah
On Daf 4b, Rav ruled that an egg laid on the first day of Yom Tov is mutar on the second day of Yom Tov, since the two days are not considered קדושה אחת, one long period of holiness. Regarding the two days of Rosh Hashanah, Rav and Shmuel ruled, נולדה בזה אסורה בזה – An egg laid on the first day of Yom Tov is prohibited on the second day of Yom Tov. Rashi explains that these two days were certainly established as one long Yom Tov, as the second day of Yom Tov was not originally observed on account of doubt. A Mishnah relates that originally, עדות החודש was accepted the entire day. Once the witnesses were delayed in coming, and assuming that no witnesses would come that day, the Leviim erred in the daily shir. Because of this, the sages enacted that Beis Din would only accept witnesses until the afternoon tamid was offered, and if witnesses came afterward, נוהגין אותו היום קדש ולמחר קדש – they would keep that day and the following day kodesh. We see that a continuous two-day Rosh Hashanah was decreed when witnesses arrived after the afternoon tamid. Rabbah said that after the Beis Hamikdash was destroyed, when Rabban Yochanan ben Zakkai enacted that Beis Din would accept witnesses for עדות החודש the entire day, an egg laid on the first day of Rosh Hashanah became permitted on the second day. Rashi explains that the since the second day was only kept out of doubt, the two days of Rosh Hashanah were treated like other Yomim Tovim, and the egg was permitted because one of the days was actually chol.
- כל דבר שבמנין צריך מנין אחר להתירו
Rav Yosef disputed Rabbah’s ruling and said that even from the time of Rabban Yochanan ben Zakkai’s takanah and onward, when they accepted witnesses the entire day of Rosh Hashana, an egg laid on the first day of Rosh Hashanah remains prohibited on the second day. הוי דבר שבמנין וכל דבר שבמנין צריך מנין אחר להתירו – Because the prohibition on the egg was a law passed by an assembly of sages, and any law passed by ballot requires another ballot to repeal it. Rashi explains that an assembly of sages must formally rescind the enactment, even though its rationale no longer exists. Rav Yosef brings three proofs for this principle, the first one based on the passuk when Hashem told Moshe at Har Sinai: "לך אמר להם שובו לכם לאהליכם" – Go say to them: Return to your tents. The Gemara explains that earlier Moshe told the Jews, "היו נכנים לשלשת ימים אל תגשו אל אשה" - Be prepared for (after) three days; do not come close to a woman. Why then was there a need for an explicit directive after the revelation to permit the resumption of relations? We see from here that כל דבר שבמנין צריך מנין אחר להתירו. Rashi on Daf 5b, explains that since HaKadosh Boruch Hu authored the prohibition against marital relations, the prohibition remained in force, even though its usefulness elapsed, until Hashem Himself rescinded it. So too, if a prohibition was enacted by an assembly of sages, an assembly of sages is needed to repeal it.
- Rav Yosef’s third proof from כרם רבעי
Rav Yosef’s third source for כל דבר שבמנין צריך מנין אחר להתירו, was from a takanah that required all כרם רבעי (produce of the fourth year) that was within a day’s travel to Yerushalayim, to be brought up to Yerushalayim and not be redeemed on money. Ullah explained that the reason was לעטר שוקי ירושלים בפירות – to adorn the markets of Yerushalayim with fruit. A Baraisa was brought that relates that when Rebbe Eliezer wanted to be mafkir his produce for the poor because it was too difficult for him to take them to Yerushalayim, his talmidim told him that the decree had been rescinded. The Gemara explains that Rav Yosef brought this third proof to demonstrate that even though the enactment to bring the kerem revai produce to Yerushalayim was from the Rabbanon, and not like the first two which were d’Oraysas enacted by Hashem, it still required Beis Din to rescind the takanah.
