“To illustrate the point of legitimacy-beyond-legality, consider the American Nazi party, the Flat Earth Society, and Hustler magazine. All three are quite legal, but they lack legitimacy. We acquiesce in their presence as the price we pay for living in a free society; but we refuse to take them seriously as "legitimate" expressions of political action, scientific inquiry or literary endeavor.”

Reportedly first said by Holmes in a speech in 1904, alternately phrased as "Taxes are what we pay for civilized society, including the chance to insure", Compania General De Tabacos De Filipinas v. Collector of Internal Revenue, 275 U.S. 87, 100, dissenting; opinion (21 November 1927). The first variation is quoted by the IRS above the entrance to their headquarters at 1111 Constitution Avenue.
1900s

Source: To run a constitution, 1986, p. x.

Source: The Sand Pebbles (1962), Ch. 5; speech of Lt. Collins
Context: Civilians are only morally bound to salute our flag. We are legally bound. All Americans are morally bound to die for our flag, if called upon. Only we are legally bound. Only we live our lives in a day to day readiness for that sacrifice. We have sworn our oaths and cut our ties. We have given up wealth and home life, except as San Pablo is our home. It marks us. It sets us apart. We are uncomfortable reminders, in time of peace. Those of you who served in the last war know what I mean.

Harvard University address (1978)

Letter to Barack Obama (2013)

On Occupy Wall Street movement, Rep. Peter King Calls Occupy Wall Street Protesters 'Ragtag Mob,' 'Anarchists' http://www.huffingtonpost.com/2011/10/07/peter-king-occupy-wall-street_n_1000318.html, 2011

The Courting of Dinah Shadd (1890).
Other works

Source: No Logo: Taking Aim at the Brand Bullies 1999, Chapter Eight, "Corporate Censorship"

Scotland in the World Forum (February 4, 2008), Church of Scotland (May 25, 2009)