The mezuza on the door of the Chamber of Parhedrin TB Yoma 10

 The mitzva of affixing a mezuza upon the doorpost of our house is found in the first paragraph of the Shema (Deuteronomy 6:9) “inscribe them on the doorpost of your house and gates.” Seven days preceding Yom Kippur, the High Priest was sequestered in the Chamber of Parhedrin. On today’s daf Yoma 10 everybody agrees that this chamber had a mezuza; however, the rabbis hold that the placing a mezuza there is Torah obligation while Rabbi Yehuda holds that it is only a rabbinic enactment.

“The Rabbis taught: None of the chambers in the Temple had a mezuza except for the Chamber of Parhedrin, in which there was a place of residence of the High Priest. Only residences in which one sleeps require a mezuza, and the only chamber in the Temple that fits that description was the Parhedrin chamber.

“Rabbi Yehuda said: That is not the reason; after all, weren’t there several chambers in the Temple in which there was a place of residence designated for priests to sit and sleep, and yet they did not have a mezuza? Rather, the mezuza in the Chamber of Parhedrin was there because there was a rabbinic decree.” (Sefaria.org translation)

The Gemara cites a contradiction between two of Rabbi Yehuda’s opinions. Here he holds that the Chamber of Parhedrin’s mezuza is only a rabbinic decree, but holds that a sukkah, even though we dwell in the sukkah for seven days like the high priest before Yom Kippur in the Chamber of Parhedrin, needs a mezuza according to Torah law. The amoraim try to reconcile Rabbi Yehuda’s opinions. The Gemara concludes that there is a qualitative difference between the Chamber of Parhedrin and the sukkah.

“The Rabbis hold: A residence in which one resides involuntarily is nevertheless considered a residence. Although the High Priest resides in the Parhedrin chamber due to a mitzva and not of his own volition, its legal status is that of a residence and a mezuza must be affixed. And Rabbi Yehuda holds: A residence in which one resides involuntarily is not considered a residence. Therefore, there should be no obligation to affix a mezuza in the Parhedrin chamber, just as there is no obligation to do so in the other Temple chambers in which priests reside. However, the Sages instituted this obligation by rabbinic law so that people will not say: The High Priest is imprisoned in jail, as only in substandard residences that appear unfit for residence is there no obligation to affix a mezuza.” (Sefaria.org translation)

As long as we are learning about the mezuza on the Parhedrin chamber’s door, now would be a good time to review some basic laws of the mezuza. “The mezuza should be affixed to every door (except that of the bathroom even if there be many rooms in the house even if the room has more than one door and even one of the stores is normally used. As long as the door can be used as an entrance and an exit, a mezuza should be affixed to the doorpost (Y.D 286)… The mezuza should be affixed within the upper third of the doorpost, and should be attached diagonal with the upper and tilted toward the house or inside the room (Y.D 289:6)… Only a permanent residence as to affix a mezuza. If one lives in a house 30 days is considered a permanent resident (Y.D 286: 22).” (A Guide to Jewish Religious Practice by Isaac Klein, page 50) For more laws and for specific questions, consult your local rabbi.