He Who Can, Does. He Who Can't, Teaches

This oft quoted phrase harks back to George Bernard Shaw (1903). However, Shaw was referring to revolutionaries, not teachers, so perhaps the phrase is used out of context. Charles H. Mayo, one of the founders of the Mayo Clinic once said: "The safest thing for a patient is to be in the hand of a (wo)man involved in teaching medicine. In order to be a teacher of medicine, the doctor must always be a student."