“I do not regard the Negro as my equal, and positively deny that he is my brother, or any kin to me whatever.”

AP report with lead summarizing of remarks stating "Robert F. Kennedy said yesterday that the United States — despite Alabama violence — is moving so fast in race relations a Negro could be President in 40 years." "Negro President in 40 Years?" in Montreal Gazette (27 May 1961) http://news.google.com/newspapers?nid=1946&dat=19610527&id=y40tAAAAIBAJ&sjid=F50FAAAAIBAJ&pg=5424,5208719
Context: The Irish were not wanted there [when his grandfather came to Boston]. Now an Irish Catholic is president of the United States … There is no question about it. In the next 40 years a Negro can achieve the same position that my brother has. … We have tried to make progress and we are making progress … we are not going to accept the status quo. … The United States Government has taken steps to make sure that the constitution of the United States applies to all individuals.

Fourth Lincoln-Douglas Debate (Charleston, 18 September 1858)
1850s, Lincoln–Douglas debates (1858)
Context: While I was at the hotel to-day, an elderly gentleman called upon me to know whether I was really in favor of producing perfect equality between the negroes and white people. While I had not proposed to myself on this occasion to say much on that subject, yet as the question was asked me, I thought I would occupy perhaps five minutes in saying something in regard to it. I will say then that I am not, nor ever have been, in favor of bringing about in any way the social and political equality of the white and black races, that I am not, nor ever have been, in favor of making voters or jurors of negroes, nor of qualifying them to hold office, nor to intermarry with white people; and I will say in addition to this that there is a physical difference between the white and black races which I believe will forever forbid the two races living together on terms of social and political equality. And inasmuch as they cannot so live, while they do remain together there must be the position of superior and inferior, and I as much as any other man am in favor of having the superior position assigned to the white race. I say upon this occasion I do not perceive that because the white man is to have the superior position the negro should be denied every thing. I do not understand that because I do not want a negro woman for a slave I must necessarily want her for a wife. My understanding is that I can just let her alone. I am now in my fiftieth year, and I certainly never had a black woman for either a slave or a wife. So it seems to me quite possible for us to get along without making either slaves or wives of negroes. I will add to this that I have never seen, to my knowledge, a man, woman, or child who was in favor of producing a perfect equality, social and political, between negroes and white men... I have never had the least apprehension that I or my friends would marry negroes if there was no law to keep them from it, but as Judge Douglas and his friends seem to be in great apprehension that they might, if there were no law to keep them from it, I give him the most solemn pledge that I will to the very last stand by the law of this State, which forbids the marrying of white people with negroes.

The Devil (Ivan's Nightmare)
The Brothers Karamazov (1879–1880)

Ch. VII, Social Problems in the Forest, p. 130 https://archive.org/stream/ontheedgeofthepr007259mbp#page/n163/mode/2up (1924 translation by Ch. Th. Campion); Schweitzer later repudiated such statements, saying "The time for speaking of older and younger brothers has passed.", as quoted in [Forrow, Lachlan, Foreword, Russell, C.E.B., African Notebook, Syracuse University Press, Albert Schweitzer library, 2002, 978-0-8156-0743-4, http://books.google.com/books?id=qa-TVXEkY3sC&pg=PR13, 23 June 2017, xiii]
Variant:
The African is my brother — but he is my younger brother by several centuries.
As quoted in The Observer (23 October 1955)
On the Edge of the Primeval Forest (1922)

1860s, Letter to Abraham Lincoln (1863)

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 93.

Source: Liberty, Equality, Fraternity (1873-1874), Ch. 1
Context: I am not the advocate of Slavery, Caste, and Hatred, nor do I deny that a sense may be given to the words, Liberty, Equality, and Fraternity, in which they may be regarded as good. I wish to assert with respect to them two propositions.
First, that in the present day even those who use those words most rationally — that is to say, as the names of elements of social life which, like others, have their advantages and disadvantages according to time, place, and circumstance — have a great disposition to exaggerate their advantages and to deny the existence, or at any rate to underrate the importance, of their disadvantages.
Next, that whatever signification be attached to them, these words are ill-adapted to be the creed of a religion, that the things which they denote are not ends in themselves, and that when used collectively the words do not typify, however vaguely, any state of society which a reasonable man ought to regard with enthusiasm or self-devotion.

As quoted in Fateful Lightning: A New History of the Civil War and Reconstruction https://books.google.com/books?id=Tpb7HAIhWHgC&printsec=frontcover&dq=9780199843282&hl=en&sa=X&ved=0ahUKEwjz1ILxqfLcAhVDnuAKHda9Ai0Q6AEIKDAA#v=onepage&q=9780199843282&f=false (2012), by Allen C. Guelzo, Chapter One

Black Boy (1945)