Babylonian Talmud, Eruvin 13b:

Rabbi Abba said in the name of Shmuel: "For three years there was a dispute between Beit Shammai and Beit Hillel, the former saying: 'The law follows our views,' and the latter saying: 'The law follows our views.' A voice from heaven problaimed: 'Both are words of the living God, but the law follows Beit Hillel."

Hillel and Shammi were the two great rabbinic leaders at the end of the first century, BCE, and each headed a school of thought (Beit = House of) which significantly shaped rabbinic Judaism as we know it today, in the period just prior to and following the destruction of the Second Temple in the year 70 CE. Over 300 of their halakhic desputes are recorded in the Talmud.

Commentary:
In this most famous selection from Talmud Eruvin, the voice of God (bat kol, lit, daughter of a voice; small voice) reveals the correct ruling while maintaining that both reflect God's truth. The passage confirms the importance of both determining some normative, accepted behavior and of accepting the truth in many approaches and interpretations.