1
general::
Phrase(s): Practice what you preach.
Prov. Cliché You yourself should do the things you advise other people to do. • Dad always told us we should only watch an hour of television every day, but we all knew he didn’t practice what he preached.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Behave as you would have others behave, as in You keep telling us to clean up, but I wish you'd practice what you preach. This idiom expresses an ancient idea but appeared in this precise form only in 1678. Also see DO AS I SAY.
American Heritage Idioms