Source and decoding - Eruvin 13b
יָצְאָה בַּת קוֹל וְאָמְרָה: אֵלּוּ וָאֵלּוּ דִּבְרֵי אֱלֹהִים חַיִּים הֵן, וַהֲלָכָה כְּבֵית הִלֵּל.
For three years Beit Shammai and Beit Hillel disputed, each saying the halacha follows us.
For three years Beit Shammai and Beit Hillel disputed, each saying the halacha follows us. A heavenly voice declared: these and these are words of the living God, and the halacha follows Beit Hillel. The Gemara explains that Beit Hillel were gentle and humble, and taught Beit Shammai’s views before their own.