Variant: I will prove myself strong when they think I am sick. I will prove myself brave when they think I am weak -Cady Sinclair
Source: We Were Liars
“In the old days, the navigators used magic to make themselves strong, but now, nothing; they just pray. Before they leave and at sea, they pray. But I, I make myself strong by thinking—just by thinking! I make myself strong because I despise cowardice. Too many men are afraid of the sea. But I am a navigator.”
The Last Navigator (1987)
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Mau Piailug 11
Micronesian navigator from the Carolinian island of Satawal… 1932–2010Related quotes

Interview on Good Day Atlanta (4 February 2011) http://www.myfoxatlanta.com/dpp/good_day_atl/Actress-Jennifer-Beals-of-The-Chicago-Code-20110204-gda-sd/.

“I am afraid I am not in the flight for “aerial navigation.””
I was greatly interested in your work with kites; but I have not the smallest molecule of faith in aerial navigation other than ballooning or of expectation of good results from any of the trials we hear of. So you will understand that I would not care to be a member of the aëronautical Society.
As a response to Major B. F. S. Baden Powell's request to join the Aeronautical Society, December 8, 1896 http://zapatopi.net/kelvin/papers/letters.html#baden-powell.
Often reproduced out of context and without citation to any primary source as "Heavier-than-air flying machines are impossible", like in The Experts Speak : The Definitive Compendium of Authoritative Misinformation (1984) by Christopher Cerf and Victor Navasky, p. 236

"Prayer helped Defoe bounce back", interview with Football Focus (22 December 2006) http://news.bbc.co.uk/sport2/hi/football/football_focus/6200993.stm.

“I feel strong. Not strong enough to face myself, but strong enough to keep going.”
Source: A Million Little Pieces

Talking to his son James http://politicalwire.com/archives/2008/11/04/fear_and_strength.html on the night of his landslide victory over Herbert Hoover (8 November 1932), as quoted in Traitor to His Class: The Privileged Life and Radical Presidency of Franklin Delano Roosevelt (2008) by H. W. Brands
1930s

in a letter to Frédéric Bazille from Etretat, December 1868; as cited in: Mary Tompkins Lewis (2007) Critical Readings in Impressionism and Post-Impressionism. p. 83
1850 - 1870