Sisyphus, as  translated by R. G. Bury, and revised by J. Garrett http://www.wku.edu/~jan.garrett/302/critias.htm 
Variant translation: He was a wise man who originated the idea of God.
                                    
“A wise man first thinks and then speaks and a fool speaks first and then thinks.”
Nahj al-Balagha
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Ali 124
cousin and son-in-law of the Islamic prophet Muhammad 601–661Related quotes
The Works of Ben Jonson, Second Folio (1640), Timber: or Discoveries
                                        
                                        Ben Jonson 
Misattributed
                                    
“Just you think first, and don’t bother to speak afterward, either.”
                                        
                                        “Catch That Rabbit”, p. 71 
I, Robot (1950)
                                    
“The fool doth think he is wise, but the wise man knows himself to be a fool.”
                                        
                                        Touchstone, Act V, scene i 
Source: As You Like It (1599–1600)
                                    
“The fool doth think he is wise, but the wise man knows himself to be a fool.”
                                        
                                        Touchstone, Act V, scene i 
Misattributed
                                    
                                        
                                        André Breton or the Quest of the Beginning 
Alternating Current (1967)
                                    
“Wise men speak when they have something to say, fools speak because they have to say something”
                                        
                                        "Necessary Observations", Precept 18 
Poems (pub. 1638)