“This amendment supplies that defect, and allows Congress to correct the unjust legislation of the States, so far that the law which operates upon one man shall operate equally upon all. Whatever law punishes a white man for a crime shall punish the black man precisely in the same way and to the same degree. Whatever law protects the white man shall afford equal protection to the black man. Whatever means of redress is afforded to one shall be afforded to all. Whatever law allows the white man to testify in court shall allow the man of color to do the same.”

1880s, Speech to the 'Boys in Blue' (1880)
Context: And it did gentle the condition and elevate the heart of every worthy soldier who fought for the Union, [applause, ] and he shall be our brother forevermore. Another thing we will remember: we will remember our allies who fought with us. Soon after the great struggle began, we looked behind the army of white rebels, and saw 4,000,000 of black people condemned to toil as slaves for our enemies; and we found that the hearts of these 4,000,000 were God-inspired with the spirit of Liberty, and that they were all our friends. [Applause. ] We have seen the white men betray the flag and fight to kill the Union; but in all that long, dreary war we never saw a traitor in a black skin. [Great cheers. ] Our comrades escaping from the starvation of prison, fleeing to our lines by the light of the North star, never feared to enter the black man's cabin and ask for bread. ["Good, good," "That's so," and loud cheers. ] In all that period of suffering and danger, no Union soldier was ever betrayed by a black man or woman. [Applause. ] And now that we have made them free, so long as we live we will stand by these black allies. [Renewed applause. ] We will stand by them until the sun of liberty, fixed in the firmament of our Constitution, shall shine with equal ray upon every man, black or white, throughout the Union. [Cheers. ] Fellow-citizens, fellow-soldiers, in this there is the beneficence of eternal justice, and by it we will stand forever. [Great applause. ] A poet has said that in individual life we rise, "On stepping-stones of our dead selves to higher things," and the Republic rises on the glorious achievements of its dead and living heroes to a higher and nobler national life. [Applause. ] We must stand guard over our past as soldiers, and over our country as the common heritage of all. [Applause. ]

"Not Palaces" (l. 23–25)

Letter to the General Assembly (1792)

1900s, Letter to Winfield T. Durbin (1903)

Journal of Discourses, vol. 10, 1863, p. 110.
1860s

Compromise proposal http://www.civilwarcauses.org/comp.htm#Jefferson%20Davis%20of%20Mississippi (24 December 1860)
1860s

1850s, The House Divided speech (1858)
Context: The new year of 1854 found slavery excluded from more than half the States by State constitutions, and from most of the national territory by congressional prohibition. Four days later commenced the struggle which ended in repealing that congressional prohibition. This opened all the national territory to slavery, and was the first point gained. But, so far, Congress only had acted; and an indorsement by the people, real or apparent, was indispensable to save the point already gained and give chance for more. This necessity had not been overlooked; but had been provided for, as well as might be, in the notable argument of "squatter sovereignty," otherwise called "sacred right of self government," which latter phrase, though expressive of the only rightful basis of any government, was so perverted in this attempted use of it as to amount to just this: That if any one man, choose to enslave another, no third man shall be allowed to object.

As quoted in His Brother's Blood: Speeches and Writings, 1838–64 https://books.google.com/books?id=qMEv8DNXVbIC&pg=PA170 (2004), edited by William Frederick Moore and Jane Ann Moore, p. 170
1850s, The Fanaticism of the Democratic Party (February 1859)

Yet Another Effort, Frenchmen, If You Would Become Republicans
Philosophy in the Bedroom (1795)