“In the tradition of American constitutionalism, all men are equally endowed by their Creator with certain rights. The equality of man is understood in the light of man's inequality with God: because men are not and never can become God or gods — because unqualified wisdom is never available to human beings — only government by the consent of the governed, and under the rule of law, is intrinsically in accordance with the eternal order.”

1920s, Speech on the Anniversary of the Declaration of Independence (1926)
Context: If all men are created equal, that is final. If they are endowed with inalienable rights, that is final. If governments derive their just powers from the consent of the governed, that is final. No advance, no progress can be made beyond these propositions. If anyone wishes to deny their truth or their soundness, the only direction in which he can proceed historically is not forward, but backward toward the time when there was no equality, no rights of the individual, no rule of the people. Those who wish to proceed in that direction can not lay claim to progress. They are reactionary. Their ideas are not more modern, but more ancient, than those of the Revolutionary fathers.

2000s, Bush's Lincolnian Challenge (2002)

Obergefell v. Hodges http://www.supremecourt.gov/opinions/14pdf/14-556_3204.pdf (26 June 2015), pp. 16-17.
2010s

1770s, Declaration of Independence (1776)

1850s, The Present Aspect of the Slavery Question (1859)
Context: Such is the present aspect of the slavery question. For myself, I believe that the faith in which the government was founded still survives. I believe that the spirit of despotism which now says to the country, 'I will rule or ruin', will hear the imperial voice of the conscience of the American people, recognizing that justice and prosperity walk hand in hand, saying, 'You will do neither'. I believe that God did not hide this continent through all time as the spot whereon a nation should be planted upon the only principle that can render a nation as permanent as the race, to suffer the experiment to fail within a century. I believe these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain inalienable rights, that among these are life, liberty, and the pursuit of happiness. Do you believe it? If aye, let us go into the battle, and God speed the right.

2000, The Spirit of the Liturgy (2000)

If we build strong and long, we must build upon moral principle.
1860s, The Good Fight (1865)

Day of Affirmation Address (1966)
Context: The road toward equality of freedom is not easy, and great cost and danger march alongside us. We are committed to peaceful and nonviolent change, and that is important for all to understand — though all change is unsettling. Still, even in the turbulence of protest and struggle is greater hope for the future, as men learn to claim and achieve for themselves the rights formerly petitioned from others. And most important of all, all of the panoply of government power has been committed to the goal of equality before the law, as we are now committing ourselves to the achievement of equal opportunity in fact. We must recognize the full human equality of all of our people before God, before the law, and in the councils of government. We must do this, not because it is economically advantageous, although it is; not because the laws of God command it, although they do; not because people in other lands wish it so. We must do it for the single and fundamental reason that it is the right thing to do.