1) AGADAH: THE "TALIS" OF A TALMID CHACHAM
OPINIONS: Rav Yehudah states that one who acts arrogantly by wearing the "Talis of a Talmid Chacham" when he in fact is not a Talmid Chacham is not permitted to enter the "Mechitzah of Hash-m." He derives this from the verse, "Gever Yahir v'Lo Yinveh" -- "the arrogant man shall not abide in his home" (Chabakuk 2:5). Rav Yehudah explains that the word "Yinveh" is similar to the word in the verse, "El Neveh Kodshecha" -- "to Your holy domain" (Shemos 15). Accordingly, the verse in Chabakuk teaches that an arrogant person will not be allowed entrance to an inner sanctum with Hash-m.
What is the "Talis of a Talmid Chacham" of which Rav Yehudah speaks?
(a) The RASHBAM (DH Kol ha'Misga'eh) explains that the "Talis of a Talmid Chacham" refers to the meticulous behavior of the Talmid Chacham. In those days, a man used to wear a cloak over a long shirt. A Talmid Chacham was careful not to let a Tefach of the garment which he wore under his robe show from under his cloak. The Rashbam understands that this was a sign of great modesty. Some commentaries explain that the reason why this was considered modest behavior is that in case his shirt would ride up, only one Tefach of his skin would show, as opposed to the amount of flesh exposed on those who wore short robes. People who were not on the level of a Talmid Chacham who would dress in this manner were acting as impostors.
(b) The IYUN YAKOV explains that one who wears the "Talis of a Talmid Chacham" is one who "steals" the Divrei Torah of a great Talmid Chacham and pretends that it is his own words of wisdom.
The BEN YEHOYADA has difficulty with both the explanation of the Rashbam and that of the Iyun Yakov. If the problem of dressing like a Talmid Chacham is arrogance, the Gemara should say outright that whoever is arrogant will not be allowed entrance to an inner sanctum with Hash-m. If it means that one "steals" Divrei Torah, the problem is not one of arrogance but of theft and Geneivas Da'as, whereby one makes others think that he is more intelligent and creative than he really is.
(c) The BEN YEHOYADA therefore explains that when the Gemara calls the person who wears the Talis of a Talmid Chacham "arrogant," it is not describing the outcome of the act, but rather the cause of the actg. One who wears the Talis of a Talmid Chacham is not acting arrogantly; rather, his arrogance is what causes him to wear such garments in the first place. The Ben Yehoyada explains that since the person is not actually a Talmid Chacham and yet, out of his arrogance, he dons the garments of a Talmid Chacham, he causes a Chilul Hash-m when he acts in his normal manner (which is not at all befitting of a Talmid Chacham) while he wears clothing that makes him look like a Talmid Chacham. This is why Hash-m shuns him. (Y. MONTROSE)
2) AGADAH: LIGHTER THAN BRAN
OPINIONS: The Gemara quotes Sefer Ben Sira, in which Ben Sira states that he weighed everything with a scale but found nothing lighter than "Subin" -- "bran." Less than bran is a Chasan who lives in the home of his father-in-law. Less than such a Chasan is a guest who invites a guest. Less than such a guest is one who answers before he hears. What is the common denominator of all of these things?
(a) The RASHBAM explains that when Ben Sira begins by saying that nothing is lighter than bran, he does not mean that bran is the worst thing in the world. If this is what he means, he would have mentioned the inedible parts of the wheat and not the bran, which is edible. Rather, he means that it is a lowly item. It seems that the Rashbam understands that the things listed by Ben Sira are common only in that they are all lowly things. They are not connected with each other in any other way.
(b) The IYUN YAKOV similarly states that the Gemara here mentions things that are lowly in people's eyes. He understands that the Gemara's reference to bran alludes to a person who gives bread made out of bran to a poor person. Ben Sira continues to mention about things that are lowly in people's eyes.
(c) The MAHARSHA explains that when Ben Sira refers to nothing being lighter than "Subin," he is not referring to actual bran, but to people who pay back their loans with merchandise of inferior quality. Although the Halachah is that such a repayment is acceptable (since the merchandise has monetary worth), it is not something which people want. Therefore, paying back a loan in such a manner is considered a lowly act.
Worse than this is a son-in-law who lives in his father-in-law's home, living off of the largesse of his father-in-law. The son-in-law comes to help himself to anything in the house, and, worse, he views himself as the cause for the abundance that is in his father-in-law's house, as though he were Yakov in the house of Lavan.
Worse than this is the guest who constantly makes himself at home in his host's house, and who firmly believes that he is the cause of the blessing of wealth that his host receives. After all, he reasons, the Chachamim teach that, "More than the homeowner does for the poor person, the poor person does for the homeowner." Such a guest is worse than a Chasan who lives in his father-in-law's house, because he takes the liberty to invite into the house visitors whom his host might not want in his house.
Ben Sira concludes that worse than such a guest is the person who answers before he hears the question. The Maharsha explains that this refers to one who happened to get the answer right, even though he did not fully hear the question. He thinks to himself that he is so intelligent; "not only did I give the right answer, but I did not even need to hear the entire question!" This attitude ultimately dooms him, because he thinks that he can give brilliant answers while hearing only half of the question. In the end, he will end up showing everyone how foolish he really is.
(It is possible that the Maharsha also means that in the case of the borrower who pays back merchandise of inferior quality, the borrower thinks that Hash-m anyway compensates the lender for giving him a loan. It therefore makes no difference whether he pays back the lender in a way which is not in his best interest. This explanation matches the other three cases, in which the Maharsha explains that the person views himself either as the cause of blessing or as unrealistically intelligent.)
(d) The ETZ YOSEF explains that these things are all things which a person might think are good, but actually are bad. One might think that bran is good to eat, when really it is not good to eat. Similarly, one might think that there is nothing wrong with moving in with one's father-in-law; after all, he is now part of his father-in-law's family. However, this is incorrect, because the son-in-law may end up being suspected of having relations with his mother-in-law, and his mother-in-law might be suspected of funneling money to her son-in-law against her husband's will.
Similarly, a guest might think that since the host likes having guests, he may feel free to bring more guests into the home. However, the opposite is true. Just because the host allows the first guest into his home does not mean that he wants another guest whom he does not even know.
Even worse is one who answers before he hears the question. The person thinks that this is the best possible way to answer; since the questioner seeks an answer, let him have the answer as soon as possible! However, the opposite is true. When a person bothers to ask a question, he wants to ascertain that the listener has heard his question and understands all of the details of the question. (Y. MONTROSE)