A rabbi summarized all of Jewish law while standing on one foot

Challenged by a would-be convert to teach the entire Torah while standing on one leg, Hillel the Elder reportedly answered: 'What is hateful to you, do not do to your neighbour. That is the whole Torah; the rest is commentary.' The story appears in the Babylonian Talmud, centuries before a similar phrasing was attributed to Jesus.

— Hillel the Elder, Babylonian Talmud, Shabbat 31a — 1st century BC