The Nazi propagandist Josef Goebbels is generally thought to have said that «If you tell a lie big enough and keep repeating it, people will eventually come to believe it». In fact, he didn’t state that, exactly, but based his propaganda largely on the premise that «credibility alone must determine whether propaganda output should be true or false». What he did say, however, was «the English follow the principle that when one lies, one should lie big, and stick to it. They keep up their lies, even at the risk of looking ridiculous»...
Source