For three years there was a dispute between Beis Shammai and Beis Hillel, the former asserting, “Halacha is in accordance with our views,” and the latter contending, “Halacha is in accordance with our views.” Eventually, a bat kol (heavenly voice) rang out and announced: “these and those are both the words of the living G-d – both views represent a valid understanding of Torah law – but in practice, the halacha follows Beis Hillel.”
(Eruvin 13b)
(Eruvin 13b)