“We strain to renew our capacity for wonder, to shock ourselves into astonishment once again.”

Source: The Martian Chronicles

Introducing Barack Obama in College Green, he later denied plagiarism despite 36 of his first 48 words being the exact same as an earlier speech by Obama. Irish Central http://www.irishcentral.com/news/Enda-Kenny-denies-plagiarizing-Barack-Obama-speech-from-2008-122512474.html
2010s

Source: Man’s Search for Himself (1953), p. 138

Attributed to Madison by Frederick Nymeyer in Progressive Calvinism: Neighborly Love and Ricardo's Law of Association, January 1958, p. 31. The source is given there as the 1958 calendar of Spiritual Motivation. It subsequently appeared in Rousas John Rushdoony, The Institutes of Biblical Law (1973), p. 541; Jerry Falwell, Listen America! (1980), p. 51; David Barton, The Myth of Separation Between Church and State (1989); and William J. Federer, America's God and Country Encyclopedia of Quotations (1994) p. 411. David Barton has since declared it "unconfirmed" after Madison scholars reported that this statement appears nowhere in the writings or recorded utterances of James Madison. http://www.members.tripod.com/candst/boston2.htm It appears to be an expansion and corruption of Madison's reference (Federalist Papers XXXIX) to "that honourable determination which animates every votary of freedom, to rest all our political experiments on the capacity of mankind for self government."
Misattributed

"A Call for Prayer – and Action -- Against Violence in America" (2012)

Introduction
The Culture of Cities (1938)
Context: Nothing is permanent: certainly not the frozen images of barbarous power with which fascism now confronts us. Those images may easily be smashed by an external shock, cracked as ignominiously as the fallen Dagon, the massive idol of the heathen; or they may be melted, eventually, by the internal warmth of normal men and women. Nothing endures except life: the capacity for birth, growth, and renewal. As life becomes insurgent once more in our civilization, conquering the reckless thrust of barbarism, the culture of cities will be both instrument and goal.

The John Clifford Lecture at Coventry (14 July 1930), published in This Torch of Freedom (1935), p. 42.
1930

Humor in Psychotherapy (2007)