Gemara

(Rav Yehudah): Yosef died before his brothers because he conducted himself with authority.

Berachos 55a (Rav Yehudah): Conducting oneself with authority shortens life;

(Rav Chama bar Chanina): Yosef lived ten years less than any of his brothers because he acted with authority.

64a (R. Avin ha'Levi): Whoever makes excessive efforts to attain wealth or grandeur will not attain it. Anyone who does not receive now what he was entitled to will receive it later. We learn from Rabah and Rav Yosef.

Chachamim of Eretz Yisrael said that (Rav Yosef, who knew all the Mishnayos and Beraisos like they were given on) Sinai has precedence over Oker Harim (Rabah, whose sharp reasoning uprooted mountains) to be Rosh Yeshiva. Still, Rav Yosef did not accept, for astrologers said that he would reign for two years. (Presumably, they would end with his death.) Rabah reigned for 22 years. During this time, Rav Yosef did not call a blood-letter to his house.

Kesuvos 103b: Before Rebbi died, he taught his son Gamliel how the Nasi should act: sit among the great Chachamim, and instill fear in the Talmidim.

Objection: We learned that "He will honor those who fear Hash-m" refers to Yehoshafat, who would rise from his throne to hug and kiss Chachamim, and would greet them 'Rebbi, Rebbi, my teacher, my teacher'!

Answer: That was in private. In public, one instills fear.

Kidushin 70a: Rav Yehudah saw Rav Nachman building a Ma'akah (railing) around his roof.

Rav Yehudah: Shmuel forbids a community leader to work in front of three people!

Pesachim 87b (R. Yochanan): Woe to authority. It causes its bearers to die early! Every Navi (of the four who prophecized at the same time, Hoshe'a, Yeshayah, Amos and Michah,) outlived four kings - "Chazon Yeshayah...(bi'Mei Uziyah Yosam Achaz Yechizkiyahu Malchei Yehudah)."

Yoma 86b: Authority buries its bearers. One enters it bare, and leaves bare. One can only hope that he will leave (guiltless) like he entered!

When Rav would go to judge, he would say (about himself) 'do I accept liability to die (if I err), without commanding about my estate, and I receive no gain from this?! May Hash-m help me to return guiltless, like I came!'

Rishonim

The Rif and Rosh (Berachos 43a and 9:4) bring Rav Chama's proof from Yosef that conducting with authority shortens one's life.

Ri'az (in Shiltei ha'Giborim 8): R. Chananel says that this refers to in private. It is permitted in public, e.g. a Nasi.

Rebuttal (Maharsha Chidushei Agados DH veha'Manhig): This is difficult. One who was appointed may act with authority! Rav Yehudah warns against conducting oneself with authority, i.e. he was not appointed and rules over the Tzibur against their will. In this case, authority buries its bearers! Even though this does not apply to Yosef, the verse is extra for this Drashah.

Note: We learned that authority buries its bearers from the Nevi'im who outlived Malchei Yehudah, including Chizkiyah. Perhaps the Maharsha holds that also here, the verse does not apply to them; it is extra for this Drashah.

Rambam (Hilchos Talmud Torah 4:5): A teacher should not be exacting when a matter is too difficult for the Talmidim to understand. If it is clear that they did not understand due to slackening from Torah, he must get angry at them and verbally shame them to sharpen them. Regarding this, it says 'instill fear in Talmidim.'

Migdal Oz: The Rambam answers the contradiction between 'a teacher should not be exacting (Avos 2:5) and 'instill fear in the Talmidim.'

Rambam (Hilchos Sanhedrin 25:4): A community leader may not work in front of three people, lest he be disgraced in front of them. All the more so, he may not eat, drink and get drunk in front of many and in gatherings of Amei ha'Aretz and feasts of merriment.

Rashi (Horayos 14a DH Umna): While Rabah ruled, Rav Yosef avoided any conduct of authority, even calling a blood-letter to his house. Some say that he learned in front of Rabah constantly, without interrupting even to let blood.

Taz (YD 336 1, b'Sof): His reward for this humility was that he had no need for doctors.

Poskim

Shulchan Aruch (YD 246:11): A teacher should not be exacting when a matter is too difficult for the Talmidim to understand. If clearly they did not understand due to slackening from Torah, he must get angry at them and verbally shame them to sharpen them. Regarding this, it says 'instill fear in Talmidim.' Therefore, a Rebbi should not act lightheaded or jest in front of the Talmidim, nor eat and drink with them, so his fear will be on them and they will learn quickly from him.

Rema (21): If one plans to engage in Torah so he will not need to work and will be supported from Tzedakah, this is Chilul Hash-m and a disgrace to Torah. Some permit. Therefore, the custom is that people of the city support the Rav of the city, lest he need to work in front of people and Torah be disgraced in the eyes of the masses.

Shulchan Aruch (334:18): If a Rav appointed by the authorities is not a Rav in Torah, he cannot excommunicate for his honor.

Rema: All the more so, one who conducts with authority due to his wealth or lineage cannot excommunicate for his honor.

Source (Beis Yosef DH Kosvu Od): Only a Talmid or Chacham whose only occupation is Torah can excommunicate for his honor. One appointed by the authorities cannot (Teshuvas ha'Rashba 245, attributed to the Ramban).