Also see Philosophy and Religion, Faith and Prayer, and Religious Humor.

• All are lunatics, but he who can analyze his delusions is called a philosopher. (Ambrose Bierce)
• All great truths begin as blasphemies. (George Bernard Shaw)
• All men are tempted. There is no man that lives that cannot be broken down, provided it is the right temptation, put in the right spot. (Henry Ward Beecher)
• All religions are founded on the fear of the many and the cleverness of the few. (Stendhal)
• Be true to your own highest convictions.
• The beauty of religious mania is that it has the power to explain everything. Once God (or Satan) is accepted as the first cause of everything which happens in the mortal world, nothing is left to chance...logic can be happily tossed out the window. (Stephen King)
• Being good is commendable, but only when it is combined with doing good is it useful.
• A belief is not true just because it is useful. (Henri F. Amiel)
• Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense. (Buddha)
• Believe those who are seeking the truth. Doubt those who find it. (Andre Gide)
• The Bible is a wonderful source of inspiration for those who don't understand it. (George Santayana)
• The Bible is not my book, and Christianity is not my religion. I could never give assent to the long, complicated statements of Christian dogma. (Abraham Lincoln)
• The biblical account of Noah's Ark and the Flood is perhaps the most implausible story for fundamentalists to defend. Where, for example, while loading his ark, did Noah find penguins and polar bears in Palestine? (Judith Hayes)
• A casual stroll through the lunatic asylum shows that faith does not prove anything. (Friedrich Nietzsche)
• Death is for many of us the gate of hell; but we are inside on the way out, not outside on the way in. (George Bernard Shaw)
• Deeds of kindness are equal in weight to all the commandments. (Talmud)
• Doubt is not a pleasant state of mind, but certainty is absurd. (Voltaire)
• Each religion, by the help of more or less myth, which it takes more or less seriously, proposes some method of fortifying the human soul and enabling it to make its peace with its destiny. (George Santayana)
• Eternity is not something that begins after you are dead. It is going on all the time. We are in it now. (Charlotte Perkins Gilman)
• Every day people are straying away from the church and going back to God. (Lenny Bruce)
• Every religion is true one way or another. It is true when understood metaphorically. But when it gets stuck in its own metaphors, interpreting them as facts, then you are in trouble. (Joseph Campbell)
• Faith and doubt both are needed - not as antagonists, but working side by side to take us around the unknown curve. (Lillian Smith)
• Faith is a lazy way of trying to get what we want, without doing anything at all.
• "Faith" means not wanting to know what is true. (Friedrich Nietzsche)
• Fundamentalists are to Christianity what paint-by-numbers is to art. (Robin Tyler)
• Genuine tragedies in the world are not conflicts between right and wrong. They are conflicts between two rights. (Georg Hegel)
• God enters by a private door into each individual. (Ralph Waldo Emerson)
• God made everything out of nothing. But the nothingness shows through. (Paul Valéry)
• God is not a cosmic bellboy for whom we can press a button to get things done. (Harry Emerson Fosdick)
• God is not what you imagine or what you think you understand. If you understand you have failed. (Saint Augustine)
• God offers to every mind its choice between truth and repose. Take which you please; you can never have both. (Ralph Waldo Emerson)
• Going to church does not make you a Christian anymore than going to MacDonald's makes you a hamburger or going to a garage makes you a mechanic.
• Great spirits have always encountered violent opposition from mediocre minds. (Albert Einstein)
• The hands that help are better far than the lips that pray. (Robert G. Ingersoll)
• He who takes a stand is often wrong, but he who fails to take a stand is always wrong.
• Hell begins the day that God grants you the vision to see all that you could have done, should have done, and would have done, but did not do. (Goethe)
• Here is the test to find whether your mission on earth is finished. If you're alive, it isn't. (Richard Bach)
• A heretic is a man who sees with his own eyes. (Gotthold Ephraim Lessing)
• The hottest places in Hell are reserved for those who, in times of great moral crisis, maintain their neutrality. (Dante Aligher)
• I can live with doubt and uncertainty. I think it's much more interesting to live not knowing than to have answers which might be wrong. (Richard P. Feynman)
• I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours. (Stephen Roberts)
• I do not believe in a fate that falls on men however they act; but I do believe in a fate that falls on them unless they act. (G. K. Chesterton)
• I do not believe in personal immortality; it seems so unnecessary. Show me one man who deserves to live forever. (Edward Abbey)
• I do not consider it an insult, but rather a compliment to be called an agnostic. I do not pretend to know where many ignorant men are sure - that is all that agnosticism means.
• I do not myself belive that any person who is really profoundly humane can believe in everlasting punishment. (Bertrand Russell)
• I don't believe in an afterlife, so I don't have to spend my whole life fearing hell, or fearing heaven even more. For whatever the tortures of hell, I think the boredom of heaven would be even worse. (Isaac Asimov)
• I don't believe in God because I don't believe in Mother Goose. (Clarence Darrow)
• I don't believe in God but I'm very interested in her. (Arthur C. Clarke)
• I have never understood why it should be considered derogatory to the Creator to suppose that he has a sense of humor. (William Ralph Inge)
• I respect faith, but doubt is what gives you an education. (Wilson Mizner)
• I'd rather live in a world where my life is surrounded by mystery than live in a world so small that my mind could comprehend it. (Harry Emerson Fosdick)
• An idea is not responsible for the people who believe it.
• If a man would follow, today, the teachings of the Old Testament, he would be a criminal. If he would follow the teachings of the new, he would be insane. (Robert G. Ingersoll)
• If fifty million people believe a foolish thing, it is still a foolish thing.
• If we wish to make a new world we have the material ready. The first one, too, was made out of chaos. (Robert Quillen)
• If your religion makes you kinder than I, your religion is better than mine. (Bradford Leavitt)
• If you're headed in the wrong direction, God allows U-turns.
• Imagination is the eye of the soul. (Joseph Joubert)
• In spite of all the yearnings of men, no one can produce a single fact or reason to support belief in God and in personal immortality. (Clarence Darrow)
• Is man one of God's blunders, or is God one of man's? (Friedrich Nietzsche)
• It can do truth no service to blink the fact...that a large portion of the noblest and most valuable teaching has been work not only of men who did not know, but of men who knew and rejected the Christian faith. (John S. Mills)
• It has been my experience that folks who have no vices have very few virtues. (Abraham Lincoln)
• It is convenient that there be gods, and, as it is convenient, let us believe that there are. (Ovid)
• It is now quite lawful for a Catholic woman to avoid pregnancy by a resort to mathematics, though she is still forbidden to resort to physics or chemistry. (H. L. Mencken)
• It is wonderful how much time good people spend fighting the devil. If they would only expend the same amount of energy loving their fellow men, the devil would die in his own tracks of ennui. (Helen Keller)
• Make of yourself a light. (Buddha)
• Man prefers belief to the exercise of judgment. (Seneca)
• A man's ethical behavior should be based effectually on sympathy, education, and social ties and needs; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death. (Albert Einstein)
• Martyrdom has always been a proof of the intensity, never the correctness, of a belief. (Arthur Schweitzer)
• Maybe this world is another planet's hell. (Aldous Huxley)
• The measure of a man's real character is what he would do if he knew he would never be found out. (T.B. Macaulay)
• Modern man is the missing link between apes and human beings.
• The Moral Majority is neither.
• The more I study religions the more I am convinced that man never worshipped anything but himself. (Richard Burton)
• The most important things are the hardest to say, because words diminish them. (Stephen King)
• Mother Nature is wonderful. A million years ago she didn't know we were going to need glasses, but look where she put our ears.
• My atheism is true piety towards the universe and denies only gods fashioned by men in their own image, to be servants of their human interests. (George Santayana)
• My life has a superb cast, but I can't figure out the plot.
• Never give the devil a ride he will always want to drive.
• Never let your sense of morals prevent you from doing what is right. (Isaac Asimov)
• No man ever believes that the Bible means what it says: He is always convinced that it says what he means. (George Bernard Shaw)
• Not that the incredulous person doesn't believe in anything. It's just that he doesn't believe in everything. (Umberto Eco)
• One certainly has a soul; but how it came to allow itself to be enclosed in a body is more than I can imagine. I only know if once mine gets out, I'll have a bit of a tussle before I let it get in again to that of any other. (Lord Byron)
• One of the misfortunes of our time is that in getting rid of false shame, we have killed off so much real shame as well. (Louis Kronenberger)
• The one thing that doesn't abide by majority rule is a person's conscience. (Harper Lee)
• The only thing necessary for the triumph of evil is for good men to do nothing.  (Edmund Burke)
• The only Zen you can find on the tops of mountains is the Zen you bring up there. (Robert M. Pirsig)
• Our greatest pretenses are built up not to hide the evil and the ugly in us, but our emptiness. The hardest thing to hide is something that is not there. (Eric Hoffer)
• Our lives begin to end the day we become silent about the things that matter. (Martin Luther King Jr.)
• Our sun is one of 100 billion stars in our galaxy. Our galaxy is one of billions of galaxies populating the universe. It would be the height of presumption to think that we are the only living things in that enormous immensity. (Wernher von Braun)
• People don't seem to realize that doing what's right is no guarantee against misfortune. (William McFee)
• People who want to share their religious views with you almost never want you to share yours with them.
• A philosopher is a person who doesn't care which side his bread is buttered on; he knows he eats both sides anyway. (Joyce Brothers)
• Philosophy is a game with objectives and no rules. Mathematics is a game with rules and no objectives.
• The pious pretense that evil does not exist only makes it vague, enormous and menacing. (Aleister Crowley)
• Prayer: To ask the laws of the universe to be annulled on behalf of a single petitioner confessedly unworthy. (Ambrose Bierce)
• Preach not to others what they should eat, but eat as becomes you and be silent. (Epictetus)
• Religion is regarded by the common people as true, by the wise as false, and by rulers as useful.
• Religion...is the opium of the masses. (Karl Marx)
• Science is what you know, philosophy is what you don't know. (Bertrand Russell)
• Sometimes I think we're alone. Sometimes I think we're not. In either case, the thought is staggering. (Buckminster Fuller)
• Tell door to door 'religious salesmen' to read Luke 10:7 ("Go not from house to house...")
• There are many in the world who are dying for a piece of bread, but there are many more dying for a little love. (Mother Teresa)
• There are many things in life that will catch your eye, but only a few will catch your heart...pursue those.
• There are people in the world so hungry, that God cannot appear to them except in the form of bread. (Mahatma Gandhi)
• There can be no happiness if the things we believe in are different from the things we do. (Freya Stark)
• There is not one big cosmic meaning for all, there is only the meaning we each give to our own life. (Anais Nin)
• There is only one religion, though there are a hundred versions of it. (George Bernard Shaw)
• There is something Pagan in me that I cannot shake off. In short, I deny nothing, but doubt everything. (Lord Byron)
• There seems to be a terrible misunderstanding on the part of a great many people to the effect that when you cease to believe you cease to behave. (Louis Kronenberger)
• A thing is not necessarily right because a man dies for it. (Oscar Wilde)
• Those who never rebelled against God or at some point in their lives shaken their fists in the face of heaven, have never encountered God at all. (Catherine Marshall)
• Throughout history, it has been the inaction of those who could have acted; the indifference of those who should have known better; the silence of the voice of justice when it mattered most; that has made it possible for evil to triumph. (Haile Selassie)
• To give pleasure to a single heart by a single act is better than a thousand heads bowing in prayer. (Ghandi)
• The trouble with life isn't that there is no answer, it's that there are so many answers.
• The true meaning of religion is thus, not simply morality, but morality touched by emotion. (Matthew Arnold)
• The truth is, hardly any of us have ethical energy enough for more than one really inflexible point of honor. (George Bernard Shaw)
• Two hands working can do more than a thousand clasped in prayer.
• The ultimate measure of a man is not where he stands in moments of comfort, but where he stands at times of challenge and controversy. (Martin Luther King, Jr.)
• The universe is not required to be in perfect harmony with human ambition.
• The universe is full of magical things patiently waiting for our wits to grow sharper. (Eden Phillpotts)
• The universe may have a purpose, but nothing we know suggests that, if so, this purpose has any similarity to ours. (Bertrand Russell)
• We can believe what we choose. We are answerable for what we choose to believe. (John Henry Newman)
• We cannot bear to regard ourselves simply as playthings of blind chance; we cannot admit to feeling ourselves abandoned. (Ugo Betti)
• We must respect the other fellow's religion, but only in the same sense and to the extent that we respect his theory that his wife is beautiful and his children smart. (Henry L. Mencken)
• We pay a high price for being intelligent. Wisdom hurts. (Euripides)
• What a person believes is not as important as how a person believes. (Timothy Virkkala)
• What is right for one soul may not be right for another. It may mean having to stand on your own and do something strange in the eyes of others. (Eileen Caddy)
• What is right is often forgotten by what is convenient. (Bodie Thoen)
• What is the first business of one who practices philosophy? To get rid of self-conceit. For it is impossible for anyone to begin to learn that which he thinks he already knows. (Epictetus)
• What matters is not the difference between believing and not believing
  but the difference between caring and not caring. (Abbe Pire)
• What men usually ask of God when they pray is that two and two not make four.
• What the caterpillar calls the end of the world the master calls a butterfly. (Richard Bach)
• When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle. (Edmund Burke)
• When it comes time to die...make sure all you have to do is die.
• When you look into an abyss, the abyss also looks into you. (Friedrich Nietzche)
• Where there is the necessary technical skill to move mountains, there is no need for the faith that moves mountains. (Eric Hoffer)
• Who can protest and does not, is an accomplice in the act. (Talmud)
• The world is a dangerous place to live, not because of the people who are evil, but because of the people who don't do anything about it. (Albert Einstein)
• The world needs anger. The world often continues to allow evil because it isn't angry enough. (Bede Jarrett)
• You have not converted a man because you have silenced him. (John Morley)