“In the great Declaration of our principles, it didn't say that all men are created equal 'if you so choose.' It said that all are created equal by the power and the will of God, and that we must respect their rights as we respect that will.”

Sixth Lincoln-Douglas debate https://cwcrossroads.wordpress.com/2011/01/18/race-and-slavery-north-and-south-some-logical-fallacies/#comment-47553, (13 October 1860), Quincy, Illinois
1860s
Context: You know that in his Charleston speech, an extract from which he has read, he declared that the negro belongs to an inferior race; is physically inferior to the white man, and should always be kept in an inferior position. I will now read to you what he said at Chicago on that point. In concluding his speech at that place, he remarked, 'My friends, I have detained you about as long as I desire to do, and I have only to say let us discard all this quibbling about this man and the other man-this race and that race, and the other race being inferior, and therefore they must be placed in an inferior position, discarding our standard that we have left us. Let us discard all these things, and unite as one people throughout this land until we shall once more stand up declaring that all men are created equal'. Thus you see, that when addressing the Chicago Abolitionists he declared that all distinctions of race must be discarded and blotted out, because the negro stood on an equal footing with the white man; that if one man said the Declaration of Independence did not mean a negro when it declared all men created equal, that another man would say that it did not mean another man; and hence we ought to discard all difference between the negro race and all other races, and declare them all created equal.

1850s, Speech on the Dred Scott Decision (1857)
Context: I think the authors of that notable instrument intended to include all men, but they did not intend to declare all men equal in all respects. They did not mean to say all were equal in color, size, intellect, moral developments, or social capacity. They defined with tolerable distinctness, in what respects they did consider all men created equal; equal in "certain inalienable rights, among which are life, liberty, and the pursuit of happiness." This they said, and this meant. They did not mean to assert the obvious untruth, that all were then actually enjoying that equality, nor yet, that they were about to confer it immediately upon them. In fact they had no power to confer such a boon. They meant simply to declare the right, so that the enforcement of it might follow as fast as circumstances should permit. They meant to set up a standard maxim for free society, which should be familiar to all, and revered by all; constantly looked to, constantly labored for, and even though never perfectly attained, constantly approximated, and thereby constantly spreading and deepening its influence, and augmenting the happiness and value of life to all people of all colors everywhere. 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, nor 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. I have now briefly expressed my view of the meaning and objects of that part of the Declaration of Independence which declares that "all men are created equal".

2000s, Is Diversity Good? (2003)
Context: To allow slavery to be introduced into free territories, where it had not hitherto existed, was, Abraham Lincoln held, a very bad thing. His opponent, Stephen A. Douglas, held that it was a sacred right, belonging to the people of each territory, to decide for themselves whether or not to have slavery among their domestic institutions. According to Douglas, Lincoln wanted to destroy the diversity upon which the union had subsisted, by insisting that all the states ought to be free. But for Douglas himself, the principle of 'popular sovereignty' did not admit of exceptions. There was to be no diversity, no deviation from the right of the people to decide. For Lincoln the wrongness of slavery meant that no one, and no people, had the right to decide in its favor. For Lincoln, the principle of human equality, "that all men are created equal", did not admit exceptions.

Source: Words of a Sage : Selected thoughts of African Spir (1937), p. 44 - (Gandhi said the same thing in All men are brothers; Simone Weil too, at the beginning of L'enracinement (the translator).

Those are undeniable truths.
Vietnamese Proclamation of Independence (2 September 1945), Ho Chi Minh, Selected Works (1960-1962), Vol. 3, pp. 17-21

Aristotle, Politics, Book V 1301a.29-31
Politics

Attributed

Letter to longtime friend and slave-holder Joshua F. Speed (24 August 1855)
1850s, Letter to Joshua F. Speed (1855)
Context: You enquire where I now stand. That is a disputed point. I think I am a whig; but others say there are no whigs, and that I am an abolitionist. When I was at Washington I voted for the Wilmot Proviso as good as forty times, and I never heard of any one attempting to unwhig me for that. I now do more than oppose the extension of slavery.
I am not a Know-Nothing. That is certain. How could I be? How can any one who abhors the oppression of negroes, be in favor of degrading classes of white people? Our progress in degeneracy appears to me to be pretty rapid. As a nation, we began by declaring that "all men are created equal." We now practically read it "all men are created equal, except negroes." When the Know-Nothings get control, it will read "all men are created equal, except negroes, and foreigners, and catholics." When it comes to this I should prefer emigrating to some country where they make no pretence of loving liberty — to Russia, for instance, where despotism can be take pure, and without the base alloy of hypocracy [sic].

1850s, Speech at Peoria, Illinois (1854)
Context: Little by little, but steadily as man's march to the grave, we have been giving up the OLD for the NEW faith. Near eighty years ago we began by declaring that all men are created equal; but now from that beginning we have run down to the other declaration, that for SOME men to enslave OTHERS is a “sacred right of self-government.” These principles can not stand together. They are as opposite as God and mammon; and whoever holds to the one, must despise the other. [... ] Let no one be deceived. The spirit of seventy-six and the spirit of Nebraska, are utter antagonisms; and the former is being rapidly displaced by the latter.