Hillel and the Golden Rule
Once there was a gentile who came before Shammai, and said to him: "Convert me on the condition that you teach me the whole Torah while I stand on one foot. Shammai pushed him aside with the measuring stick he was holding. The same fellow came before Hillel, and Hillel converted him, saying: That which is despicable to you, do not do to your fellow, this is the whole Torah, and the rest is commentary, go and learn it."
Rabbi Hillel was one of the most influential scholars in Jewish history. Babylonian Talmud, Shabbat 31a