“Proof itself, of any sort, is impossible, without an axiom (as Godel proved). Thus faith in God is a prerequisite for all proof.”

The second sentence is often misquoted as “Science has proof without any certainty. Creationists have certainty without any proof.” or “Religion gives us certainty without proof; science gives us proof without certainty.”
Context: Bigotry and science can have no communication with each other, for science begins where bigotry and absolute certainty end. The scientist believes in proof without certainty, the bigot in certainty without proof. Let us never forget that tyranny most often springs from a fanatical faith in the absoluteness of one’s beliefs.

Source: Reflections and Maxims (1746), p. 184.

In a letter to Heinrich Wilhelm Matthias Olbers (14 May 1826), defending Chevalier d'Angos against presumption of guilt (by Johann Franz Encke and others), of having falsely claimed to have discovered a comet in 1784; as quoted in Calculus Gems (1992) by George F. Simmons

p, 125
New Fragments (1892)

The Art of Persuasion

Source: Utilitarianism (1861), Ch. 1
Context: I shall, without further discussion of the other theories, attempt to contribute something towards the understanding and appreciation of the Utilitarian or Happiness theory, and towards such proof as it is susceptible of. It is evident that this cannot be proof in the ordinary and popular meaning of the term. Questions of ultimate ends are not amenable to direct proof. Whatever can be proved to be good, must be so by being shown to be a means to something admitted to be good without proof.

page 305
Truth and Tension in Science and Religion

p. 138.