“Self-portraiture is something one should never get involved in, since it is wrong to lie even though one endeavours to tell the truth.”

"Aus Churchills Lügenfabrik" ("Churchill's Lie Factory"), 12 January 1941, Die Zeit ohne Beispiel (Munich: Zentralverlag der NSDAP., 1941), pp. 364-369
This and similar lines in Adolf Hitler's Mein Kampf about what he claimed to be a strategem of Jewish lies using "the principle & which is quite true in itself & that in the big lie there is always a certain force of credibility; because the broad masses of a nation are always more easily corrupted in the deeper strata of their emotional nature than consciously or voluntarily," are often misquoted or paraphrased as: "The bigger the lie, the more it will be believed."
1940s

Source: The Hunt for Red October

As quoted in The Histories by Herodotus, 3.72
The validity of the quote is questionable. http://www.shsu.edu/~his_ncp/Heropers.html
Attributed

Slobodan Milošević (2002) International Committee to Defend Slobodan Milosevic https://web.archive.org/web/20030204145956/http://www.icdsm.org/milosevic/30jan.htm

Source: The Kite Runner

Source: Light in August

Variant: Don't trust anyone. Be a cold fish. I hurt no one. And no one can hurt me.
Source: Chinese Cinderella: The True Story of an Unwanted Daughter

Source: Triton (1976), Chapter 7 “Tiresias Descending, or Trouble on Triton” (p. 329)

Source: Heartless