“Humor is mankind's greatest blessing.”

245b–c
Phaedrus

(J. Hudson Taylor. Separation and Service: Or Thoughts on Numbers VI, VII. London: Morgan & Scott, n.d., 15-16).

British Telecom advertisement (1993), part of which was used in Pink Floyd's Keep Talking (1994) and Talkin' Hawkin'<nowiki/> (2014)
Context: For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen. Speech has allowed the communication of ideas, enabling human beings to work together to build the impossible. Mankind's greatest achievements have come about by talking, and its greatest failures by not talking. It doesn't have to be like this. Our greatest hopes could become reality in the future. With the technology at our disposal, the possibilities are unbounded. All we need to do is make sure we keep talking.

Source: Don Quixote de la Mancha (1605–1615), Part II (1615), Book III, Ch. 58.

Voice of the Nile, from Odysseus' story, Book VIII, line 1290
The Odyssey : A Modern Sequel (1938)
Context: Blessed are those eyes that have seen more water than any man!
Blessed be that haughty mind that aimed at the greatest hope!
May you be blessed who row the current your life long
and now with dry unfreshened lips descend to Hades
to find the hidden deathless springs and slake your thirst!
My son, it's death who keeps and pours the deathless waters.

"Credo" (1991); also in Greetings, Carbon-Based Bipeds! : Collected Essays, 1934-1998 (1999), p. 360
1990s

Speech at the unveiling of a bust of the late Canadian Prime Minister Sir John Macdonald at Westminster Abbey (16 November 1892), reported in The Times (17 November 1892), p. 9. Leo McKinstry, Rosebery: Statesman in Turmoil (John Murray, 2006), p. 120.