“When a stupid man is doing something he is ashamed of, he always declares that it is his duty.”
Act III http://books.google.com/books?id=3wAOAQAAMAAJ
Source: 1890s, Caesar and Cleopatra (1898)
Help us to complete the source, original and additional information
George Bernard Shaw 413
Irish playwright 1856–1950Related quotes

On death, in an interview for the documentary Mandela (1994). Source: From Nelson Mandela By Himself: The Authorised Book of Quotations © 2010 by Nelson R. Mandela and The Nelson Mandela Foundation http://www.nelsonmandela.org/content/mini-site/selected-quotes
1990s
Source: Plan B: Further Thoughts on Faith

“A fellow who is always declaring he's no fool usually has his suspicions.”
"Maxims Old and New", All of a Piece: New Essays https://books.google.com/books?id=4vEQAAAAMAAJ&focus=searchwithinvolume&q=%22A+fellow+who+is+always+declaring+he%27s+no+fool+usually+has+his+suspicions.%22 (1937), edited by Edward Verrall Lucas, p. 52.
Epigrams

Source: I, Claudius (1934), Ch. 5.
Context: My tutor I have already mentioned, Marcus Porcius Cato who was, in his own estimation at least, a living embodiment of that ancient Roman virtue which his ancestors had one after the other shown. He was always boasting of his ancestors, as stupid people do who are aware that they have done nothing themselves to boast about. He boasted particularly of Cato the Censor, who of all characters in Roman history is to me perhaps the most hateful, as having persistently championed the cause of "ancient virtue" and made it identical in the popular mind with churlishness, pedantry and harshness.

Source: What is Philosophy? (1964), pp. 16-17