Thomas Jefferson, letter to Samuel Adams Wells, May 12, 1821:

The Declaration of Independence… [is the] declaratory charter of our rights, and the rights of man.

Thomas Jefferson, letter to John Adams, September 12, 1821:

[T]he flames kindled on the 4 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.

James Madison, letter to Thomas Jefferson, February 8, 1825:

On the distinctive principles of the Government …of the U. States, the best guides are to be found in…The Declaration of Independence, as the fundamental Act of Union of these States.

Thomas Jefferson, letter to Henry Lee, May 8, 1825:

This was the object of the Declaration of Independence. Not to find out new principles, or new arguments, never before thought of, not merely to say things which had never been said before; but to place before mankind the common sense of the subject, in terms so plain and firm as to command their assent, and to justify ourselves in the independent stand we are compelled to take. Neither aiming at originality of principle or sentiment, nor yet copied from any particular and previous writing, it was intended to be an expression of the American mind, and to give to that expression the proper tone and spirit called for by the occasion.