גמרא שבת י"ז.:ו'
אָמַר לוֹ: אִם תַּקְנִיטֵנִי – גּוֹזְרַנִי טוּמְאָה אַף עַל הַמְּסִיקָה. נָעֲצוּ חֶרֶב בְּבֵית הַמִּדְרָשׁ, אָמְרוּ: הַנִּכְנָס – יִכָּנֵס, וְהַיּוֹצֵא – אַל יֵצֵא. וְאוֹתוֹ הַיּוֹם הָיָה הִלֵּל כָּפוּף וְיוֹשֵׁב לִפְנֵי שַׁמַּאי כְּאֶחָד מִן הַתַּלְמִידִים, וְהָיָה קָשֶׁה לְיִשְׂרָאֵל כַּיּוֹם שֶׁנַּעֲשָׂה בּוֹ הָעֵגֶל", וּגְזוּר שַׁמַּאי וְהִלֵּל וְלָא קַבִּלוּ מִינַּיְיהוּ, וַאֲתוֹ תַּלְמִידַיְיהוּ גְּזוּר וְקַבִּלוּ מִינַּיְיהוּ.
Shammai said to him: If you provoke me and insist that there is no difference between gathering olives and grapes, then, in order not to contradict this, I will decree impurity on the gathering of olives as well. They related that since the dispute was so intense, they stuck a sword in the study hall, and they said: One who seeks to enter the study hall, let him enter, and one who seeks to leave may not leave, so that all of the Sages will be assembled to determine the halakha. That day Hillel was bowed and was sitting before Shammai like one of the students. The Gemara said: And that day was as difficult for Israel as the day the Golden Calf was made, as Hillel, who was the Nasi, was forced to sit in submission before Shammai, and the opinion of Beit Shammai prevailed in the vote conducted that day.
The explanation is that the Rambam paskens that the Nasi of the Sanhedrin is like Moshe Rabbeinu [Sanhedrin 1-3]. Hillel was the Nasi. After the חטא העגל Hashem told Moshe "לך רד" - which Chazal interpret to mean "Descend from your greatness" - "רד מגדולתך". So the day the Nasi descended from HIS greatness and sat humbly before Shammai was like the day of the חטא העגל.
[מרן ראש הישיבה זצ"ל]
