Blood and Guts in High School (1978)
“Are you hero enough to unite yourself to one whom you know to be suspected and despised by all around you, and identify your interests and your honour with hers? Think! it is a serious thing.”
Source: The Tenant of Wildfell Hall (1848), Ch. XII : A Tête-à-tête and a Discovery; Gilbert and Helen
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Anne Brontë 148
British novelist and poet 1820–1849Related quotes

Variant translations
If you know others and know yourself, you will not be imperiled in a hundred battles; if you do not know others but know yourself, you win one and lose one; if you do not know others and do not know yourself, you will be imperiled in every single battle.
Know your enemy and know yourself, find naught in fear for 100 battles. Know yourself but not your enemy, find level of loss and victory. Know not thy enemy nor yourself, wallow in defeat every time.
Literal translation: Know [the] other, know [the] self, hundred battles without danger; not knowing [the] other but know [the] self, one win one loss; not knowing [the] other, not knowing [the] self, every battle must [be] lost.
Source: The Art of War, Chapter III · Strategic Attack

Nelson Mandela on humour, From an interview with Tim Couzens, Verne Harris and Mac Maharay for Mandela: The Authorized Portrait, 2006 (13 August 2005). Source: From Nelson Mandela By Himself: The Authorised Book of Quotations © 2010 by Nelson R. Mandela and The Nelson Mandela Foundation http://www.nelsonmandela.org/content/mini-site/selected-quotes
2000s

Session 340, Page 25
The Early Sessions: Sessions 1-42, 1997, The Early Sessions: Book 8

Source: Quoted in "The Overview Effect: Space Exploration and Human Evolution" by Frank White


Television interview ("On clarity and exact thinking" - available on youtube)
1960s