In the fields of observation chance favors only the prepared mind
Lecture, University of Lille (7 December 1854)

Do not let yourself be tainted with a barren skepticism.
As quoted in The Louisville & Nashville Employes' Magazine Vol. 20 (1944)‎, p. 28

Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world. Science is the highest personification of the nation because that nation will remain the first which carries the furthest the works of thought and intelligence.
As quoted in Louis Pasteur, Free Lance of Science (1960) by René Jules Dubos, Ch. 3

Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity.
As quoted in "There's a Spiritual Solution to Every Problem" (2001) by Wayne W. Dyer

The universe is asymmetric and I am persuaded that life, as it is known to us, is a direct result of the asymmetry of the universe or of its indirect consequences.
"Works" Vol. 1 (1 June 1874) Comptes Rendus de l'Académie des Sciences

There does not exist a category of science to which one can give the name, applied science. There are science and the applications of science, bound together as the fruit of the tree which bears it.
Revue Scientifique (1871)

When I approach a child, he inspires in me two sentiments; tenderness for what he is, and respect for what he may become.

I am on the edge of mysteries and the veil is getting thinner and thinner.
Letter (December 1851); as quoted in "The Great Influenza: The Epic Story of the Deadliest Plague In History" (2004) by John M. Barry

Posterity will one day laugh at the foolishness of modern materialistic philosophers.
As quoted in "The Literary Digest" (18 October 1902)

One does not ask of one who suffers: What is your country and what is your religion? One merely says: You suffer, that is enough for me...
As quoted in "Louis Pasteur, Free Lance of Science" (1960) by René Jules Dubos, Ch. 3

Blessed is he who carries within himself a God, an ideal, and who obeys it: ideal of art, ideal of science, ideal of the gospel virtues, therein lie the springs of great thoughts and great actions; they all reflect light from the Infinite.
As quoted by Sir William Osler in his introduction to "The Life of Pasteur" (1907) by Rene Vallery-Radot

I am utterly convinced that Science and Peace will triumph over Ignorance and War, that nations will eventually unite not to destroy but to edify, and that the future will belong to those who have done the most for the sake of suffering humanity.
As quoted in "Louis Pasteur, Free Lance of Science" (1960) by René Jules Dubos, Ch. 3

Science brings men nearer to God.
As quoted in Letter to an Atheist (2007) by Michael Patrick Leahy, p. 61