“Our Constitution is color-blind, and neither knows nor tolerates classes among citizens. In respect of civil rights, all citizens are equal before the law.”

1890s, Plessy v. Ferguson (1896)

Source: Marvi Sirmed https://blogs.tribune.com.pk/story/3270/where-did-the-blasphemy-law-come-from/

1950s, Address at the Philadelphia Convention Hall (1956)
Context: The right of no nation depends upon the date of its birth or the size of its power. As there can be no second class citizens before the law of America, so—we believe—there can be no second-class nations before the law of the world community.

Dissenting, Poulos v. New Hampshire, 345 U.S. 395 (1953)
Judicial opinions

1860s, Reconstruction (1866)

His broadcast to the nation on the eve of the Republic day on 25 January 1996, in: p. 244.
Commissions and Omissions by Indian Presidents and Their Conflicts with the Prime Ministers Under the Constitution: 1977-2001

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".
1850s, Speech on the Dred Scott Decision (1857)

1920s, Letter to Charles F. Gardner (1924)
Context: Leaving out of consideration the manifest impropriety of the President intruding himself in a local contest for nomination, I was amazed to receive such a letter. During the war 500,000 colored men and boys were called up under the draft, not one of whom sought to evade it. They took their places wherever assigned in defense of the nation of which they are just as truly citizens as are any others. The suggestion of denying any measure of their full political rights to such a great group of our population as the colored people is one which, however it might be received in some other quarters, could not possibly be permitted by one who feels a responsibility for living up to the traditions and maintaining the principles of the Republican Party. Our Constitution guarantees equal rights to all our citizens, without discrimination on account of race or color. I have taken my oath to support that Constitution. It is the source of your rights and my rights. I propose to regard it, and administer it, as the source of the rights of all the people, whatever their belief or race.