The most dramatic dispute in the history of Jewish law ended with a voice from heaven — and the sages overruled it. The Talmud (Bava Metzia 59b) records the famous argument between Rabbi Eliezer ben Hyrcanus and the majority of sages over the ritual purity of the "oven of Akhnai."
Rabbi Eliezer ruled that a particular type of oven was ritually pure. Every other sage disagreed. Rabbi Eliezer marshaled every legal argument he knew, but the majority would not budge. So he turned to supernatural proof.
"If the law is as I say, let this carob tree prove it!" The tree uprooted itself and flew a hundred cubits. "A carob tree proves nothing," the sages replied. "Let the stream prove it!" The stream reversed its flow. "A stream proves nothing." "Let the walls of this study house prove it!" The walls began to lean inward, as if about to collapse. Rabbi Yehoshua rebuked the walls: "When scholars argue about law, what business is it of yours?" The walls stopped leaning but did not straighten, out of respect for both sages.
Finally, Rabbi Eliezer called on the highest authority: "Let heaven prove it!" A divine voice rang out: "Why do you argue with Rabbi Eliezer? The law is always as he says!"
Rabbi Yehoshua stood and quoted the Torah itself: "It is not in heaven" (Deuteronomy 30:12). The Torah was given at Sinai. From that moment on, legal decisions are made by the majority of sages on earth, not by voices from above. Even God's opinion, after Sinai, does not override the rabbinic process.
The Talmud adds: at that moment, God laughed and said, "My children have defeated Me. My children have defeated Me."