“I do not believe in any religion, I will have nothing to do with immortality. We are miserable enough in this life without speculating upon another.”

"Why Liberty?”, in the Chicago Tribune (30 January 1927)
1920s
Context: I believe that liberty is the only genuinely valuable thing that men have invented, at least in the field of government, in a thousand years. I believe that it is better to be free than to be not free, even when the former is dangerous and the latter safe. I believe that the finest qualities of man can flourish only in free air – that progress made under the shadow of the policeman’s club is false progress, and of no permanent value. I believe that any man who takes the liberty of another into his keeping is bound to become a tyrant, and that any man who yields up his liberty, in however slight the measure, is bound to become a slave.

"To the Indianapolis Clergy." The Iconoclast (Indianapolis, IN) (1883)

The third and fourth sentences are a paraphrase of a sentence by G. K. Chesterton: "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." Generally Speaking, "On Holland' (1928).
1980s, First term of office (1981–1985), First Inaugural address (1981)
Context: It is time for us to realize that we're too great a nation to limit ourselves to small dreams. We're not, as some would have us believe, doomed to an inevitable decline. I do not believe in a fate that will fall on us no matter what we do. I do believe in a fate that will fall on us if we do nothing. So, with all the creative energy at our command, let us begin an era of national renewal. Let us renew our determination, our courage, and our strength. And let us renew our faith and our hope. We have every right to dream heroic dreams. Those who say that we're in a time when there are no heroes, they just don't know where to look.

Philosophy in the Bedroom (1795)

Nous désirons passionnément qu'il y ait une autre vie où nous serions pareils à ce que nous sommes ici-bas. Mais nous ne réfléchissons pas que, même sans attendre cette autre vie, dans celle-ci, au bout de quelques années, nous sommes infidèles à ce que nous avons été, à ce que nous voulions rester immortellement.
Pt. II, Ch. 2
In Search of Lost Time, Remembrance of Things Past (1913-1927), Vol. IV: Cities of the Plain (1921-1922)

Reported by Representative Martin Dies as having been said in a conversation at the White House, in the Congressional Record (September 22, 1950), vol. 96, Appendix, p. A6832. Reported as "exceedingly dubious" in Paul F. Boller, Jr., Quotemanship: The Use and Abuse of Quotations for Polemical and Other Purposes, chapter 8, p. 361 (1967); Boller goes on to say that "it is most unlikely that FDR would have said anything like it, even flippantly, to the zealous HUAC chairman, though he may have told Dies that he was exaggerating the size of the American communist movement".
Misattributed

Source: The Rise of Endymion (1997), Chapter 32 (p. 665)

Source: On the Origin of Species (1859), chapter VII: "Instinct", page 207 http://darwin-online.org.uk/content/frameset?pageseq=225&itemID=F373&viewtype=side
Context: I must premise, that I have nothing to do with the origin of the primary mental powers, any more than I have with that of life itself. We are concerned only with the diversities of instinct and of the other mental qualities of animals within the same class.

Нет бессмертия души, так нет и добродетели, значит, всё позволено. … Без бога-то и без будущей жизни? Ведь это, стало быть, теперь всё позволено, всё можно делать?
The Brothers Karamazov (1879–1880)