“For my part, I favour an approach to statecraft that embraces principles, as long as it is not stifled by them; and I prefer such principles to be accompanied by steel along with good intentions.”

Vol. I: Arithmetical Algebra Preface, p. iii
A Treatise on Algebra (1842)

Independence Day speech (1828)
Context: There is, in the institutions of this country, one principle, which, had they no other excellence, would secure to them the preference over those of all other countries. I mean — and some devout patriots will start — I mean the principle of change.
I have used a word to which is attached an obnoxious meaning. Speak of change, and the world is in alarm. And yet where do we not see change? What is there in the physical world but change? And what would there be in the moral world without change?

Source: On the Road

Source: Collapse: How Societies Choose to Fail or Succeed (2005), Chapter "Big businesses and the environment: different conditions, different outcomes", section "Businesses and the public" (Penguin Books, 2011, pages 484-485, ISBN 978-0-241-95868-1.

Letter to the Reverend G. W. Snyder (24 October 1798) http://etext.virginia.edu/etcbin/toccer-new2?id=WasFi36.xml&images=images/modeng&data=/texts/english/modeng/parsed&tag=public&part=388&division=div1
1790s
Context: !-- Revd Sir I have your favor of the 17th instant before me; and my only motive to trouble you with the receipt of this letter, is to explain, and correct a mistake which I perceive the hurry in which I am obliged, often, to write letters, have led you into.
--> It was not my intention to doubt that, the Doctrines of the Illuminati, and principles of Jacobinism had not spread in the United States. On the contrary, no one is more truly satisfied of this fact than I am.
The idea that I meant to convey, was, that I did not believe that the Lodges of Free Masons in this Country had, as Societies, endeavoured to propagate the diabolical tenets of the first, or pernicious principles of the latter (if they are susceptible of seperation). That Individuals of them may have done it, or that the founder, or instrument employed to found, the Democratic Societies in the United States, may have had these objects; and actually had a seperation of the People from their Government in view, is too evident to be questioned. <!--
My occupations are such, that but little leisure is allowed me to read News Papers, or Books of any kind; the reading of letters, and preparing answers, absorb much of my time. With respect — I remain Revd Sir Your Most Obedt Hble Ser. Go: Washington

Epitaph on his grave in Lancaster, Pensylvania
1860s