Our Gemara relates that Rabbi Elazar ben Pedat taught a ruling about a nine-year-old yavam (that we classify his attempt at yibum – levirate marriage – in the same category as ma’amar), and he did not attribute the ruling to his teacher, Rabbi Yohanan, who had been the one who originally said it. Upon hearing this, Rabbi Yohanan became upset.
Seeing their teacher upset, Rav Ami and Rabbi Asi tried to calm him by relating a story. They said “Did it not happen at the synagogue of Tiberias that Rabbi Elazar and Rabbi Yose argued a point so strongly that a Sefer Torah was torn in their excitement. And Rabbi Yosei ben Kisma who was there exclaimed, ‘I would be surprised if this synagogue does not become a place of idolatrous worship’, which then, in fact, happened.” Far from calming Rabbi Yohanan, this annoyed him all the more. “You are even making us colleagues now?” he exclaimed.
At that point, Rabbi Ya’akov bar Idi came in and pointed out to him that when a student teaches any law, it is clear to all that he is merely quoting his teacher. As a prooftext he pointed to the passage in Sefer Yehoshua (11:15) in which we find that Yehoshua is complimented on carrying out all of the commandments that had been given to Moshe. This was clearly done without giving credit to Moshe on every occasion, rather it was clear to all that Yehoshua was following the instructions laid out by Moshe. Similarly, argued Rabbi Ya’akov bar Idi, all the students know that Rabbi Elazar was quoting his teacher, Rabbi Yohanan. This argument pacified Rabbi Yohanan.
Rabbi Yohanan’s complaint against Rabbi Ami and Rabbi Asi is interpreted by Rashi to mean that they were equating his student with him, just as Rabbi Eliezer and Rabbi Yose were colleagues and peers. The Iyyun Ya’akov suggests that his complaint stemmed from the fact that they were chastising him for becoming upset, in effect treating him like a peer; he felt that as his students it was inappropriate for them to respond to him in such a manner.
In his commentary to the Ein Ya’akov, the Ir Binyamin – Rabbi Binyamin Zev ben Shmuel Darshan – suggests that Rabbi Yohanan was upset because he had no sons, and he was particularly concerned that his teachings, which were his legacy, should be said in his name.