Our Declaration of Independence has been copied by emerging nations around the globe, its themes adopted in places many of us have never heard of. Here in this land, for the first time, it was decided that man is born with certain God-given rights. We the people declared that government is created by the people for their own convenience. Government has no power except those voluntarily granted it by the people. There have been revolutions before and since ours, revolutions that simply exchanged one set of rulers for another. Ours was a philosophical revolution that changed the very concept of government.
Ronald Reagan, address at Yorktown, October 19, 1981

I am well aware of the toil, and blood, and treasure, that it will cost us to maintain this declaration, and support and defend these states. Yet, through all the gloom, I can see the rays of light and glory; I can see that the end is more than worth all the means, and that posterity will triumph.
John Adams, letter to Abigail Adams, July 3, 1776

There! His Majesty can now read my name without glasses. And he can double the reward on my head!
John Hancock, upon signing the Declaration of Independence, July 4, 1776

We must all hang together, or assuredly we shall all hang separately.
Benjamin Franklin, at the signing of the Declaration of Independence, July 4, 1776

The flames kindled on the 4th of July 1776, have spread over too much of the globe to be extinguished by the feeble engines of despotism; on the contrary, they will consume these engines and all who work them.
Thomas Jefferson, letter to John Adams, September 12, 1821

Today, 186 years later, that Declaration whose yellowing parchment and fading, almost illegible lines I saw in the past week in the National Archives in Washington is still a revolutionary document. To read it today is to hear a trumpet call. For that Declaration unleashed not merely a revolution against the British, but a revolution in human affairs. . . . The theory of independence is as old as man himself, and it was not invented in this hall. But it was in this hall that the theory became a practice; that the word went out to all, in Thomas Jefferson's phrase, that "the God who gave us life, gave us liberty at the same time." And today this Nation—conceived in revolution, nurtured in liberty, maturing in independence—has no intention of abdicating its leadership in that worldwide movement for independence to any nation or society committed to systematic human oppression.
John F. Kennedy, address at Independence Hall, July 4, 1962

The assertion that "all men are created equal" was of no practical use in effecting our separation from Great Britain; and it was placed in the Declaration, not for that, but for future use. Its authors meant it to be, thank God, it is now proving itself, a stumbling block to those who in after times might seek to turn a free people back into the hateful paths of despotism. They knew the proneness of prosperity to breed tyrants, and they meant when such should re-appear in this fair land and commence their vocation they should find left for them at least one hard nut to crack.
Abraham Lincoln, speech on the Dred Scott Decision, June 26, 1857