“Traditionally, a luncheon is a lunch that takes an eon.”

Oscar Wilde, letter to Frank Harris, June 13, 1897, in The Letters of Oscar Wilde (1962) p. 608.
Criticism

Source: Burn for Me

as quoted by [Stephen Hawking, A Brief History of Time, Bantam Books, 1988, 0-553-34614-8, 129]

The Vindication of Tradition: 1983 Jefferson Lecture in the Humanities (1984), p. 65.
Alternate version" Tradition is the living faith of the dead; traditionalism is the dead faith of the living. Tradition lives in conversation with the past, while remembering where we are and when we are and that it is we who have to decide. Traditionalism supposes that nothing should ever be done for the first time, so all that is needed to solve any problem is to arrive at the supposedly unanimous testimony of this homogenized tradition.
in "Christianity as an enfolding circle," U.S. News & World Report (June 26, 1989), p. 57

Source: The 48 Laws of Power

Also often misattributed to Robert A. Heinlein because both helped popularize the expression – Friedman with a book with that title. The phrase actually dates to at least the 1930s.
Misattributed

Reply to King George VI, on a cold morning at the airport. The King had asked if Churchill would take something to warm himself. As cited in Man of the Century (2002), Ramsden, Columbia University Press, p. 134 ISBN 0231131062
Post-war years (1945–1955)