“One can insult an honest man or an honest woman, but to tell a thief that he is a thief is merely la constation d'un fait”

"Bishop Blougram’s Apology", line 395; cited by Graham Greene as the epigraph he would choose for his novels.
Men and Women (1855)

1790s, Letter to Revd. Dr. Trusler (1799)

Source: Sourcery

tr. O'Neill 1938, Perseus http://www.perseus.tufts.edu/hopper/text.jsp?doc=Aristoph.+Kn.+1274
Knights, line 1274-1275
Knights (424 BC)

Introductio ad prudentiam: Part II (1727), Gnomologia (1732)

Attributed to St. Augustine in The Repentance of Robert Greene, Master of Arts http://www.oxford-shakespeare.com/Greene/Repentance_Robert_Greene.pdf (1592) by Robert Greene.
Disputed
Variant: Do not despair; one of the thieves was saved. Do not presume; one of the thieves was damned.

Speech on Religious Intolerance as presented at the Pittsburgh Opera House (14 October 1879).
Context: They say the religion of your fathers is good enough. Why should a father object to your inventing a better plow than he had? They say to me, do you know more than all the theologians dead? Being a perfectly modest man I say I think I do. Now we have come to the conclusion that every man has a right to think. Would God give a bird wings and make it a crime to fly? Would he give me brains and make it a crime to think? Any God that would damn one of his children for the expression of his honest thought wouldn't make a decent thief. When I read a book and don't believe it, I ought to say so. I will do so and take the consequences like a man.

Source: Dragonswood