Those who can, do. Those who can't, teach.

Those who can, do. Those who can't, teach.

proverb Those who are especially skilled in a certain field or area will be able to pursue a career, while those who are less skilled will end up teaching about it instead. A: "I know he always aspired to be a great novelist, but the last I heard he's still teaching middle school English." B: "Well, those who can, do; those who can't, teach."
See also: those, who
Farlex Dictionary of Idioms.

Those who can, do; those who can't, teach.

Prov. People who are able to do something well can do that thing for a living, while people who are not able to do anything that well make a living by teaching. (Used to disparage teachers. From George Bernard Shaw's Man and Superman.) Bob: I'm so discouraged. My writing teacher told me my novel is hopeless. Jane: Don't listen to her, Bob. Remember: those who can, do; those who can't, teach.
See also: teach, those, who
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • Those who can, do; those who can't, teach
  • make good as
  • make good as (something)
  • jockstrap
  • jockstrapper
  • a Jack of all trades is a master of none
  • jack of all trades is a master of none
  • a Jill of all trades is a master of none
  • have a good command of
  • have a good command of (something)