Talmud Bavli, Eruvin
Eruvin 13b:10
In Eruvin 13b, the Talmud states that the halacha follows Beit Hillel over Beit Shammai because Beit Hillel would listen and consider the words of Beit Shammai and were known for their humility, presenting the views of Beit Shammai before their own.
אָמַר רַבִּי אַבָּא אָמַר שְׁמוּאֵל: שָׁלֹשׁ שָׁנִים נֶחְלְקוּ בֵּית שַׁמַּאי וּבֵית הִלֵּל, הַלָּלוּ אוֹמְרִים: הֲלָכָה כְּמוֹתֵנוּ, וְהַלָּלוּ אוֹמְרִים: הֲלָכָה כְּמוֹתֵנוּ. יָצְאָה בַּת קוֹל וְאָמְרָה: אֵלּוּ וָאֵלּוּ דִּבְרֵי אֱלֹהִים חַיִּים הֵן, וַהֲלָכָה כְּבֵית הִלֵּל. וְכִי מֵאַחַר שֶׁאֵלּוּ וָאֵלּוּ דִּבְרֵי אֱלֹהִים חַיִּים, מִפְּנֵי מָה זָכוּ בֵּית הִלֵּל לִקְבּוֹעַ הֲלָכָה כְּמוֹתָן? מִפְּנֵי שֶׁנּוֹחִין וַעֲלוּבִין הָיוּ, וְשׁוֹנִין דִּבְרֵיהֶן וְדִבְרֵי בֵּית שַׁמַּאי, וְלֹא עוֹד אֶלָּא שֶׁמַּקְדִּימִין דִּבְרֵי בֵּית שַׁמַּאי לְדִבְרֵיהֶן. לְלַמֶּדְךָ שֶׁכׇּל הַמַּשְׁפִּיל עַצְמוֹ — הַקָּדוֹשׁ בָּרוּךְ הוּא מַגְבִּיהוֹ, וְכׇל הַמַּגְבִּיהַּ עַצְמוֹ — הַקָּדוֹשׁ בָּרוּךְ הוּא מַשְׁפִּילוֹ. כׇּל הַמְחַזֵּר עַל הַגְּדוּלָּה — גְּדוּלָּה בּוֹרַחַת מִמֶּנּוּ, וְכׇל הַבּוֹרֵחַ מִן הַגְּדוּלָּה — גְּדוּלָּה מְחַזֶּרֶת אַחֲרָיו, וְכׇל הַדּוֹחֵק אֶת הַשָּׁעָה — שָׁעָה דּוֹחַקְתּוֹ, וְכׇל הַנִּדְחֶה מִפְּנֵי שָׁעָה — שָׁעָה עוֹמֶדֶת לוֹ.
Rabbi Abba said that Shmuel said: For three years Beit Shammai and Beit Hillel disagreed. These said: The halakha is in accordance with our opinion, and these said: The halakha is in accordance with our opinion. Ultimately, a Divine Voice emerged and proclaimed: Both these and those are the words of the living God. However, the halakha is in accordance with the opinion of Beit Hillel. The Gemara asks: Since both these and those are the words of the living God, why were Beit Hillel privileged to have the halakha established in accordance with their opinion? The reason is that they were agreeable and forbearing, showing restraint when affronted, and when they taught the halakha they would teach both their own statements and the statements of Beit Shammai. Moreover, when they formulated their teachings and cited a dispute, they prioritized the statements of Beit Shammai to their own statements, in deference to Beit Shammai. This is to teach you that anyone who humbles himself, the Holy One, Blessed be He, exalts him, and anyone who exalts himself, the Holy One, Blessed be He, humbles him. Anyone who seeks greatness, greatness flees from him, and, conversely, anyone who flees from greatness, greatness seeks him. And anyone who attempts to force the moment and expends great effort to achieve an objective precisely when he desires to do so, the moment forces him too, and he is unsuccessful. And conversely, anyone who is patient and yields to the moment, the moment stands by his side, and he will ultimately be successful.