"More than the calf wants to suck, the cow wants to give milk.” (Pesachim 112a) So said Rabbi Akiva to his student Rabbi Shimon bar Yochai noting the truism that it is the teacher who has more desire to teach than the student has to learn. But just as a king cannot reign without subjects, a teacher cannot teach without students.
While a good teacher is yearning to share their knowledge the reverse cannot always be said regarding the students. Yet whether they wanted to or not all were expected to attend the public shiur of the Rabbi, at least on Shabbat afternoon. So much so that our Sages forbade the study of the third section of Tanach, the ketuvim on Shabbat lest one get so caught up in these thrilling books that they neglect to attend the Rabbi’s shiur[1](Shabbat 115a).
“The elders of Nezunia did not come to the shiur of Rav Chisda.” (Kiddushin 25a) So upset was Rav Chisda that he instructed his colleague Rav Hamenunah to go and tell the elders of Nezunia that they should “sequester themselves” a phrase Rashi understands to mean a mild form of excommunication. Such is an appropriate response to the lack of respect[2] they displayed in staying home instead of attending the shiur[3]. Interestingly there is no record of Rav Hamenunah carrying out this instruction. Rather he asked the elders of Nezunia why they did not attend the shiur. The elders of Nezunia were baffled by the question as they responded “Why should we come? We asked him questions he could not answer.” Some questions are better not asked.
Rav Hamenunah was taken aback and responded by asking “Have you ever asked me anything, which I could not solve?” To see if Rav Hamenunah was any better than Rav Chisda the elders of Nezunia decided to test him. They asked him whether a slave would go free if his master were to injure him in his “private parts”. As we discussed in our last post a slave goes free if his master permanently injures an external organ. Would such apply in this instance? While the organ is external it is covered up and even the euphemism we use to describe them would indicate these are not regular external organs and perhaps the slave would not go free. When Rav Hamenunah answered that he did not know the elders of Nezunia asked him his name and when he responded “Hamenunah” they mocked him saying “you are not hamenunah but karnunah.” As Rashi notes the term karnunah refers to those who hang out on the street corners, yoshvei kranot, frittering away their time. So out of touch are they from the goings on of a normal society that their testimony may not be accepted in a court of law.
Interestingly while Rav Hamenunah did not know the answer to this question Rav Chisda did. In fact he seemed rather surprised that Rav Hamenunah could not figure out the halacha as it can be deduced from a clear teaching of the Mishna.
This story appears as part of the larger discussion on when a slave would go free, a discussion of little import to us today. What is important is some of the messages implicit in the story. The disrespect shown by the elders of Nezunia both in not going to Rav Chisda's shiur and in their treatment of Rav Hamenunah. While Rav Hamenunah tried to defend the honour of Rav Chisda he did so with a little too much hubris. Instead of extoling the greatness of Rav Chisda he tried to demonstrate his vast knowledge - only to fail and have Rav Chisda point out how simple the question really was. We are never told what it was that Rav Chisda could not answer. Whatever it was it paled in comparison to what he did know. 
[1] If only that were the reason people did not come to a shiur. Perhaps the reason this “prohibition” is no longer adhered to is that we  have little interest in forbidding any form of Torah study. And I dare say this even applies to Tisha B’av where the many programs that abound come awfully close, or more accurately actually cross the line, into Torah study that is technically prohibited on Tisha B’Av. Fortunate are those whose greatest sin is the study of Torah on Tisha B’av or Tanach on a nice long Shabbat afternoon. 
[2] While we tend to use the term apikorus to refer to one’s who has “unorthodox” beliefs the Talmud (Sanhedrin 99b) defines it as “one who belittles a Torah scholar”. While there is a big difference between not attending a shiur one is expected to be at and belittling a Torah scholar, it is more a matter of degree than of substance.
[3] When I had the great zechut, fortune, of studying with Nehama Leibowitz she made it quite clear that either we attended every week or we should not come at all. A Beit Midrash is not meant to be a county club where one shows up when they please to sit back and relax.