“The day may never come when it is seen as funny.”

Source: An Introduction to the Principles of Morals and Legislation (1789; 1823), Ch. 17 : Of the Limits of the Penal Branch of Jurisprudence
Context: The day has been, I grieve to say in many places it is not yet past, in which the greater part of the species, under the denomination of slaves, have been treated by the law exactly upon the same footing as, in England for example, the inferior races of animals are still. The day may come when the rest of the animal creation may acquire those rights which never could have been withholden from them but by the hand of tyranny. The French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormentor. It may one day come to be recognized that the number of legs, the villosity of the skin, or the termination of the os sacrum are reasons equally insufficient for abandoning a sensitive being to the same fate. What else is it that should trace the insuperable line? Is it the faculty of reason, or perhaps the faculty of discourse? But a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day or a week or even a month, old. But suppose they were otherwise, what would it avail? The question is not Can they reason?, nor Can they talk?, but Can they suffer?

And on that day, our nation shall fulfill its creed — and that fulfillment shall enrich us all.
What the Future Holds (1984)

Letter to Mr. B.Maddock, 10 November 1805,
Letters

Nobel Prize acceptance speech (1961)

Plunkitt of Tammany Hall, Chapter 18, On the Use of Money in Politics

Remark to J. H. Thomas (14 January 1930), quoted in Thomas Jones, Whitehall Diary, Volume II: 1926–1930 (Oxford University Press, 1969), p. 235
1930s

Source: Macbeth, Act I, scene iii.

Book of Taliesin (c. 1275?), The First Address of Taliesin