Moreshet: From the Classics

Rabbi Eliezer brought forth several proofs for an argument in the academy, but his rabbinical colleagues did not agree with him. He then said to them: “If the law agrees with me, let that locust tree prove it!” Immediately the locust tree flew out of the soil where it was rooted. His colleagues said to him: “No proof can be brought from a locust tree!” Then Eliezer spoke to them again: “If the law agrees with me, let that stream of water prove it!” Immediately, the stream of water began to flow backward. His colleagues again said: “No proof can be brought from a stream.” Then Eliezer said: “If the law agrees with me, let the walls of this academy prove it!” Immediately the walls of the academy leaned over as if they were about to fall. And before his colleagues spoke again, Eliezer said: “If the law agrees with me, let heaven itself prove it!” A voice then came forth from heaven saying: “Why do you dispute with Rabbi Eliezer? The law does agree with him in every case.” Rabbi Joshua then stood up and said: “It is not in heaven!” What did he mean by “not in heaven?” Rabbi Jeremiah said: “The Torah was given on Mount Sinai; the voice from heaven does not concern us because it is written in the Torah on Mount Sinai: “After the majority one must decide.” (Exodus 25.2)

Talmud Bava Metzia 59a