Posterity: you will never know how much it has cost my generation to preserve your freedom. I hope you will make good use of it.

Attributed in The Rebirth of a Nation : With a Bill of Rights for America's Third Century (1978) by Robert S. Minor, p. 10; this is a paraphrase of a statement by his father John Adams in a letter to his mother Abigail Adams (27 April 1777): "Posterity! you will never know how much it cost the present generation to preserve your freedom! I hope you will make a good use of it. If you do not, I shall repent in Heaven that I ever took half the pains to preserve it".