“I myself am pursuing the same instinctive course as the veriest human animal you can think of — I am, however young, writing at random — straining at particles of light in the midst of a great darkness — without knowing the bearing of any one assertion, of any one opinion. Yet may I not in this be free from sin?”

The Making of Americans (1925)

271
The Chidakasha Gita (1927)

Letter to Cadwallader Colden (23 April 1752).
Epistles

Letter to George Washington (July 1776)

On mistaking pseudorandom number generators for being truly "random" — this quote is often erroneously interpreted to mean that von Neumann was against the use of pseudorandom numbers, when in reality he was cautioning about misunderstanding their true nature while advocating their use. From "Various techniques used in connection with random digits" by John von Neumann in Monte Carlo Method (1951) edited by A.S. Householder, G.E. Forsythe, and H.H. Germond <!-- National Bureau of Standards Applied Mathematics Series, 12 (Washington, D.C.: U.S. Government Printing Office, 1951): 36-38. -->
Context: Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin. For, as has been pointed out several times, there is no such thing as a random number — there are only methods to produce random numbers, and a strict arithmetic procedure of course is not such a method.

Source: Pride and Prejudice

Conclusion : The Moral of this Examination
A Perplexed Philosopher (1892)
Context: I care nothing for creeds. I am not concerned with any one's religious belief. But I would have men think for themselves. If we do not, we can only abandon one superstition to take up another, and it may be a worse one. It is as bad for a man to think that he can know nothing as to think he knows all. There are things which it is given to all possessing reason to know, if they will but use that reason. And some things it may be there are, that — as was said by one whom the learning of the time sneered at, and the high priests persecuted, and polite society, speaking through the voice of those who knew not what they did, crucified — are hidden from the wise and prudent and revealed unto babes.

Source: Hegel's Idealism: The Satisfactions of Self-Consciousness (1989), p. 21

Response to a Serenade, November 9, 1864 http://www.gutenberg.org/dirs/3/2/5/3253/3253-h/files/2659/2659-h/2659-h.htm#2H_4_0271 (one day after the United States presidential election of 1864; in "The Papers And Writings Of Abraham Lincoln, Volume Seven, Constitutional Edition", edited by Arthur Brooks Lapsley and released as "The Project Gutenberg EBook of The Papers And Writings Of Abraham Lincoln, Volume Seven, by Abraham Lincoln" (2009) by Project Gutenberg
1860s
Context: I earnestly believe that the consequences of this day's work, if it be as you assume, and as now seems probable, will be to the lasting advantage, if not to the very salvation, of the country. I cannot at this hour say what has been the result of the election. But, whatever it may be, I have no desire to modify this opinion: that all who have labored to-day in behalf of the Union have wrought for the best interests of the country and the world; not only for the present, but for all future ages. I am thankful to God for this approval of the people; but, while deeply grateful for this mark of their confidence in me, if I know my heart, my gratitude is free from any taint of personal triumph. I do not impugn the motives of any one opposed to me. It is no pleasure to me to triumph over any one, but I give thanks to the Almighty for this evidence of the people's resolution to stand by free government and the rights of humanity.