“Religious belief prevented the growth of a sense of realism.”

1910s, Address to the Knights of Columbus (1915)
Context: One of the most important things to secure for him is the right to hold and to express the religious views that best meet his own soul needs. Any political movement directed against anybody of our fellow- citizens because of their religious creed is a grave offense against American principles and American institutions. It is a wicked thing either to support or to oppose a man because of the creed he professes. This applies to Jew and Gentile, to Catholic and Protestant, and to the man who would be regarded as unorthodox by all of them alike. Political movements directed against men because of their religious belief, and intended to prevent men of that creed from holding office, have never accomplished anything but harm. This was true in the days of the ‘Know-Nothing’ and Native-American parties in the middle of the last century; and it is just as true to-day. Such a movement directly contravenes the spirit of the Constitution itself. Washington and his associates believed that it was essential to the existence of this Republic that there should never be any union of Church and State; and such union is partially accomplished wherever a given creed is aided by the State or when any public servant is elected or defeated because of his creed. The Constitution explicitly forbids the requiring of any religious test as a qualification for holding office. To impose such a test by popular vote is as bad as to impose it by law. To vote either for or against a man because of his creed is to impose upon him a religious test and is a clear violation of the spirit of the Constitution.

Le Mystère Laïc (1928); later published in Collected Works Vol. 10 (1950)

State of Fear (2004)
Context: I think that you cannot eliminate religion from the psyche of mankind. If you suppress it in one form, it merely emerges in another form. Even if you don't believe in God, you still have to believe in something that gives meaning to your life, and shapes your sense of the world. Such a belief is religious.

Jeder hat zunächst den Gottesglauben, den man ihm aufgeschwatzt hat; aber allmählich hat er den, den er verdient.
Bissige Aphorismen, Rowohlt 1994, ISBN 3-499-22061-X, S. 14

Introduction, p. 1 (First text line.)
The Economic Illusion (1984)

Source: Friday (1982), Chapter 18 (p. 181)

Patheos, Orwellian Legislative Duplicity on HB 1485 http://www.patheos.com/blogs/reasonadvocates/2017/05/05/orwellian-legislative-duplicity-hb-1485/ (May 5, 2017)

The Atheism Tapes (2004)
Context: I have a friend — or had a friend, now dead — Abdus Salam, a very devout Muslim, who was trying to bring science into the universities in the Gulf states and he told me that he had a terrible time because, although they were very receptive to technology, they felt that science would be a corrosive to religious belief, and they were worried about it... and damn it, I think they were right. It is corrosive of religious belief, and it's a good thing too.