Because once you believe God is on your side, you get an ego the size of God's. You lose all perspective and are able to convince yourself that all of your decisions are God's will. It washes away all doubt and conscience. Your actions can no longer be questioned or judged, you are reporting to a higher power.
"The cardinal doctrine of a fanatic's creed is that his enemies are the enemies of God."
— Andrew Dickson
I distrust those people who know so well what God wants them to do because I notice it always coincides with their own desires.
— Susan B. Anthony (1820-1906)
I believe today that my conduct is in accordance with the will of the Almighty Creator.
— Adolph Hitler, Mein Kampf, pp. 46
You can safely say that you have made God in your own image when it turns out that God hates all the same people you do.
— Reverend Robert Cromey
Men never do evil so completely and cheerfully as when they do it from religious conviction.
— Blaise Pascal, (1623-1662)
The most heinous and the must cruel crimes of which history has record have been committed under the cover of religion or equally noble motives.
— Mohandas K. Gandhi; (1869-1948)
Faith, the sweetest refuge and consolation, may harden, by perverse miracle, into a sword -- or anyway into a club or a torch or an assault rifle. Religious hatreds tend to be merciless and absolute.
— Lance Morrow
It is usually when men are at their most religious that they behave with the least sense and the greatest cruelty.
— Ilka Chase
It is possible to pull out justification for imposing your will on others, simply by calling your will God's will.
— Ruth Hurmence Green
What mean and cruel things men do for the love of God.
— Somerset Maugham
What is objectionable, what is dangerous, about extremists is not that they are extreme, but that they are intolerant. The evil is not what they say about their cause, but what they say about their opponents.
— Robert F. Kennedy, (1925-1968)
Religious tolerance has developed more as a consequence of the impotence of religions to impose their dogmas on each other than as a consequence of spiritual humility.
— Sidney Hook, (1902-1989)
The doctrine which, from the very first origin of religious dissensions, has been held by bigots of all sects, when condensed into a few words and stripped of rhetorical disguise, is simply this: I am in the right, and you are in the wrong. When you are the stronger, you ought to tolerate me; for it is your duty to tolerate truth. But when I am the stronger I shall persecute you; for it is my duty to persecute error.
— Lord Macaulay, (1800-1859)
It goes with the passionate intensity and deep conviction of the truth of a religious belief, and of course of the importance of the superstitious observances that go with it, that we should want others to share it -- and the only certain way to cause a religious belief to be held by everyone is to liquidate nonbelievers. The price in blood and tears that mankind generally has had to pay for the comfort and spiritual refreshment that religion has brought to a few has been too great to justify our entrusting moral accountancy to religious belief.
— Sir Peter Medawar
I have observed that the world has suffered far less from ignorance than from pretensions to knowledge. It is not skeptics or explorers but fanatics and ideologues who menace decency and progress. No agnostic ever burned anyone at the stake or tortured a pagan, a heretic, or an unbeliever.
— Daniel Boorstin
We have just enough religion to make us hate, but not enough to make us love one another.
— Jonathan Swift, 1711