Quotes about wisdom and truth

Source: Ode on a Grecian Urn and Other Poems

The Four Cardinal Virtues: Prudence, Justice, Fortitude, Temperance (1965)

Novalis (1829)
Context: Man consists in Truth. If he exposes Truth, he exposes himself. If he betrays Truth, he betrays himself. We speak not here of lies, but of acting against Conviction.

1830s, The American Scholar http://www.emersoncentral.com/amscholar.htm (1837)

Source: The Complete Poems

De Libero Arbitrio (388 - 395)

The Drifters (1971) First lines

The Milwaukee Sentinel Princess Grace finds relaxation in her gardens Jan. 1, 1981

The Third Notebook: Part Two
Source: No Longer Human

Walking the Path of Compassion (2015)

Variant: A person who never made a mistake never tried anything new.

As quoted by LIFE magazine (2 May 1955)
1950s
Variant: Strive not to be a success, but rather to be of value.

From the same 24 March 1954 letter as above, p. 44
Attributed in posthumous publications, Albert Einstein: The Human Side (1979)

In answer to a question asked by the editors of Youth, a journal of Young Israel of Williamsburg, NY. Quoted in the New York Times, June 20, 1932, pg. 17 http://select.nytimes.com/gst/abstract.html?res=F40617F83B5A13738DDDA90A94DE405B828FF1D3
Unsourced variant: Only a life in the service of others is worth living.
1930s
Variant: I believe in one thing—that only a life lived for others is a life worth living.

Letter to his son Eduard (5 February 1930), as quoted in Walter Isaacson, Einstein: His Life and Universe (2007), p. 367
1930s

Letter to Jost Winteler (1901), quoted in The Private Lives of Albert Einstein by Roger Highfield and Paul Carter (1993), p. 79 http://books.google.com/books?id=zY7FE9ZyDO0C&lpg=PP1&pg=PA79#v=onepage&q&f=false. Einstein had been annoyed that Paul Drude, editor of Annalen der Physik, had dismissed out of hand some criticisms Einstein made of Drude's electron theory of metals.
1900s
Variant: A foolish faith in authority is the worst enemy of truth.

As quoted in Journal of France and Germany (1942–1944) by Gilbert Fowler White, in excerpt published in Living with Nature's Extremes: The Life of Gilbert Fowler White (2006) by Robert E. Hinshaw, p. 62. From the context http://books.google.com/books?id=_2qfZRp9SeEC&lpg=PP1&pg=PA62#v=onepage&q&f=false it seems that White did not specify whether he had heard Einstein himself say this or whether he was repeating a quote that had been passed along by someone else, so without a primary source the validity of this quote should be considered questionable.
Some have argued that elsewhere Einstein defined a "miracle" as a type of event he did not believe was possible—Einstein on Religion by Max Jammer (1999) quotes on p. 89 from a 1931 conversation Einstein had with David Reichinstein, where Reichinstein brought up philosopher Arthur Liebert's argument that the indeterminism of quantum mechanics might allow for the possibility of miracles, and Einstein replied that Liebert's argument dealt "with a domain in which lawful rationality [determinism] does not exist. A 'miracle,' however, is an exception from lawfulness; hence, there where lawfulness does not exist, also its exception, i.e., a miracle, cannot exist." ("Dort, wo eine Gesetzmässigkeit nicht vorhanden ist, kann auch ihre Ausnahme, d.h. ein Wunder, nicht existieren." D. Reichenstein, Die Religion der Gebildeten (1941), p. 21). However, it is clear from the context that Einstein was stating only that miracles cannot exist in a domain (quantum mechanics) where lawful rationality does not exist. He did not claim that miracles could never exist in any domain. Indeed, Einstein clearly believed, as seen in many quotations above, that the universe was comprehensible and rational, but he also described this characteristic of the universe as a "miracle". In another example, he is quoted as claiming belief in a God, "Who reveals Himself in the lawful harmony of the world."
As quoted in From Yale to Jail: The Life Story of a Moral Dissenter (1993) by David T. Dellinger, p. 418
Disputed
Variant: There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.
Variant: There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.