Quotation: "Eternal vigilance is the price of liberty."

Variations:

1. "The price of liberty is eternal vigilance."

Sources consulted: (searching on the phrase "eternal vigilance")

1. Papers of Thomas Jefferson Digital Edition
2. Thomas Jefferson: Papers and Thomas Jefferson: Biographies collections in Hathi Trust Digital Library
3. Thomas Jefferson Retirement Papers

Earliest known appearance in print: 1817 (as "eternal vigilance is the price we pay for liberty")12

Earliest known appearance in print, attributed to Jefferson: 1834: "Mr. Jefferson, the great apostle of human rights, has told us, that 'the price of Liberty is eternal vigilance.'"3

Other attributions: Patrick Henry, Junius, Wendell Phillips

Status: We currently have no evidence to confirm that Thomas Jefferson ever said or wrote, "Eternal vigilance is the price of liberty" or any of its variants.

Comments: This quotation was well-known in the nineteenth century, and was in fact used by a number of famous figures, including Frederick Douglass, James Buchanan, and William Henry Harrison. It can be traced back, ultimately, to John Philpot Curran's statement, "The condition upon which God hath given liberty to man is eternal vigilance; which condition if he break, servitude is at once the consequence of his crime and the punishment of his guilt."4  Curran was still being directly quoted (more or less accurately) and credited with the quote in American newspapers in the early 19th century, but before long the quote was being used without Curran's name, and was being shortened to its more well-known modern form.5 

• 1. "4th July, 1817, 42d year," [Bennington] Vermont Gazette, July 8, 1817, p. 2: "..."let your motto be 'eternal vigilance is the price we pay for liberty.'"
• 2. To establish the earliest appearance of this phrase in print, the following sources were searched for the phrases, "eternal vigilance" and "price of liberty": Google Books, Google Scholar, Amazon.com, Internet Archive, America's Historical Newspapers, America's Historical Imprints, Eighteenth Century Collections Online, 19th Century U.S. Newspapers, 19th Century UK Newspapers, American Periodicals Series Online, 17th-18th Century Burney Collection Newspapers.
• 3. "Communicated," Richmond Enquirer, December 30, 1834.
• 4. See Suzy Platt, ed., Respectfully Quoted (Washington, D.C.: Library of Congress, 1993), 200.
• 5. See Phila. Weekly Aurora, March 26, 1811; (Concord) New-Hampshire Patriot, April 27, 1813; Ulster Plebeian (Kingston, NY), April 2, 1816; (Bennington) Vermont Gazette, July 8, 1817.