Today, it is commonplace that someone who wants to rule in questions of Jewish law first study the material and then go to be tested in order to be “ordained” as a Rabbi, that is, receive semikha (lit. “resting of the hands”) or permission to rule from a prominent Rabbi. This system stems from the time of the Talmud, when a student would turn to the Nasi for permission to rule.
There were three areas of study, each of which required specific approval that would allow the candidate to be accepted as one who could rule in each type of case:
Yoreh – issues of ritual law
Yadin – monetary cases
Yatir bekhorot – rules of blemishes in animals that would allow a first-born animal to be used by a kohen rather than be sacrificed on the altar.
The first two categories are still in use, referred to today as “Yoreh Yoreh” and “Yadin Yadin.” The third category fell into disuse after the destruction of the Temple, although it has become common practice to avoid situations where an animal will have a first-born by selling a pregnant animal to a non-Jew, so that no such questions will arise.
Rav Menashya bar Tahalifa said that Rav Amram said that Rabba bar bar Hana said: They asked Rabbi Elazar ben Pedat: Must an Elder who sits and studies Torah in a yeshiva receive permission from the Nasi to permit him to render firstborn animals permitted, like others who must get permission from the Nasi to render firstborn animals permitted, or not? A firstborn animal may not be eaten until it has a blemish. Knowing which blemishes are permanent and permit the animal to be eaten and which are temporary is specialized knowledge.
The Gemara asks: What are they asking? What is the basis of the question? The Gemara explains: This is what they are asking, like this statement of Rav Idi bar Avin, who said: This matter, the authority of the Nasi to grant permission, was given to the house of the Nasi to raise its stature. Therefore, must permission be received, since the request itself honors the Nasi? Or, perhaps because the individual in question is an Elder who sits and studies Torah in a yeshiva, there is no need. Rav Tzadok ben Haluka rose to his feet and said: I saw Rabbi Yosei ben Zimra, who was an Elder who sat in the yeshiva and who stood before the grandfather of this current Nasi, ask permission from him to permit firstborn animals.
From the discussion that takes place, it appears that this story happens during the time that the Nasi was the second Rabbi Yehuda Nesia. By that time, the position of Nasi was inherited, and the person who held the title was not necessarily a great Torah Sage. The actual religious leadership fell to the heads of the academies – the Roshei Yeshiva. Nevertheless, a number of ceremonial responsibilities remained in the hands of the Nasi, one of them being the approval of new Rabbis and judges.
The discussion in the Gemara of whether a Sage who is already teaching in the academy needs to receive permission from the Nasi in order to rule is an indication of the tension that existed between the Sages and the house of the Nasi.