“In its main features the Declaration of Independence is a great spiritual document. It is a declaration not of material but of spiritual conceptions. Equality, liberty, popular sovereignty, the rights of man — these are not elements which we can see and touch. They are ideals. They have their source and their roots in the religious convictions. They belong to the unseen world. Unless the faith of the American people in these religious convictions is to endure, the principles of our Declaration will perish. We can not continue to enjoy the result if we neglect and abandon the cause.”

Memorial Day address, Arlington National Cemetery (31 May 1976) http://www.presidency.ucsb.edu/ws/index.php?pid=6071
1970s
Context: The founding of our Nation was more than a political event; it was an act of faith, a promise to Americans and to the entire world. The Declaration of Independence declared that people can govern themselves, that they can live in freedom with equal rights, that they can respect the rights of others.
In the two centuries that have passed since 1776, millions upon millions of Americans have worked and taken up arms when necessary to make that dream a reality. We can be extremely proud of what they have accomplished. Today, we are the world's oldest republic. We are at peace. Our Nation and our way of life endure. We are free.

1960s, Emancipation Proclamation Centennial Address (1962)

"Nihilism  On  A  Religious  Soil" (6 May 1907); it should be noted here that Berdyaev is here defining "theocracy" not in the sense as it is often used, of people ruling over other people, in claims of doing so by the commands of God, but rather defining it in terms of Christian anarchism — as a vigorous assertion of the right of no-one to rule over humans, save God.
Context: The new religious consciousness rises up against the nihilistic attitude towards the world and mankind. If a religious rebirth be possible, only then on this soil will there be the revealing of the religious meaning of secular culture and earthly liberation, the revealing of the truth about mankind. For the new religious consciousness the declaration of the will of God is together with this a declaration of the rights of man, a revealing of the Divine within mankind. We believe in the objective, the cosmic might of the truth of God, in the possibility according to God to guide the earthly destiny of mankind. This will be the victory of the true theocracy, whether over a false democratism, — the apotheosis of the quantitative collectivity of human wills, or so also over the false theocraticism, — all that apotheosis of the human will within Caesaropapism or Papocaesarism. Christ cannot have human vicarage in the person of the tsar or high-priest. He — is Himself the Tsar and High-Priest, and He will reign in the world. “Thy Kingdom come, Thy Will be done on earth, as it is in Heaven.”

1920s, Speech on the Anniversary of the Declaration of Independence (1926)

Epitaph, upon his instructions to erect a "a plain die or cube … surmounted by an Obelisk" with "the following inscription, and not a word more…because by these, as testimonials that I have lived, I wish most to be remembered." It omits that he had been President of the United States, a position of political power and prestige, and celebrates his involvement in the creation of the means of inspiration and instruction by which many human lives have been liberated from oppression and ignorance.
Posthumous publications

In Defense of Emma Goldman and the Right of Expropriation (1893)
Context: Humanity can not be made equal by declarations on paper. Unless the material conditions for equality exist, it is worse than mockery to pronounce men equal. And unless there is equality (and by equality I mean equal chances for every one to make the most of himself) unless, I say, these equal chances exist, freedom, either of thought, speech, or action, is equally a mockery.

1920s, Speech on the Anniversary of the Declaration of Independence (1926)

The Need for Transcendence in the Postmodern World (1994)

Centennial Oration (4 July 1876) http://www.infidels.org/library/historical/robert_ingersoll/centennial_oration.html
Context: p>One hundred years ago, our fathers retired the gods from politics.The Declaration of Independence is the grandest, the bravest, and the profoundest political document that was ever signed by the representatives of a people. It is the embodiment of physical and moral courage and of political wisdom.</p