You may fool all the people some of the time; you can even fool some of the people all the time; but you can't fool all of the people all the time.
(Abraham Lincoln (1809-1865), U.S. president. Quoted in "Abe" Lincoln's Yarns and Stories, p. 184, Alexander McClure (1904).
The famous aphorism has also been attributed to the showman Phineas T. Barnum.)