“Men are at war with each other because each man is at war with himself.”

La guerre, c'est un massacre de gens qui ne se connaissent pas, au profit de gens qui se connaissent, mais ne se massacrent pas.
Bizarre, issues 24-31 (1962), p. 102
This apocryphal quote from Paul Valéry is never precisely sourced: neither on the internet nor in the works we have consulted. See: https://www.guichetdusavoir.org/question/voir/52650

Lincoln Hall Speech (1879)
Context: Whenever the white man treats the Indian as they treat each other then we shall have no more wars. We shall be all alike — brothers of one father and mother, with one sky above us and one country around us and one government for all. Then the Great Spirit Chief who rules above will smile upon this land and send rain to wash out the bloody spots made by brothers' hands upon the face of the earth. For this time the Indian race is waiting and praying. I hope no more groans of wounded men and women will ever go to the ear of the Great Spirit Chief above, and that all people may be one people.

In reference to the Alabama Council on Human Relations, an organization which was joined by King, whose church's meeting room was used to hold monthly meetings for the Montgomery chapter the council. Stride Toward Freedom: The Montgomery Story (1958)
1950s
Context: Although the Montgomery council never had a large membership, it played an important role. As the only truly interracial group in Montgomery, it served to keep the desperately needed channels of communication open between the races.
Men often hate each other because they fear each other; they fear each other because they don't know each other; they don't know each other because they can not communicate; they can not communicate because they are separated. In providing an avenue of communication, the council was fulfilling a necessary condition for better race relations in the South.

James explaining one of the messages he says he receives from the extraterrestrials.

Source: The Blue Book of Freedom: Ending Famine, Poverty, Democide, and War (2007), p. 106

State v. Beal http://books.google.com/books?id=lEFOAQAAIAAJ&q=%22it+would+be+almost+unbelievable+if+history+did+not+record+the+tragic+fact+that+men+have+gone+to+war+and+cut+each+other's+throats+because+they+could+not+agree+as+to+what+was+to+become+of+them+after+their+throats+were+cut%22&pg=PA302#v=onepage, 199 N.C. 278 (1930).

Technopoly: the Surrender of Culture to Technology (1992)
Context: We can imagine that Thamus [or Amun: this is a reference to a discussion on the value of writing in Plato's Phaedrus] would also have pointed out to Gutenberg, as he did to Theuth, that the new invention would create a vast population of readers who "will receive a quantity of information without proper instruction... with the conceit of wisdom instead of real wisdom"; that reading, in other words, will compete with older forms of learning. This is yet another principle of technological change we may infer from the judgment of Thamus: new technologies compete with old ones — for time, for attention, for money, for prestige, but mostly for dominance of their world-view. This competition is implicit once we acknowledge that the medium contains an ideological bias. And it is a fierce competition, as only ideological competitions can be. It is not merely a matter of tool against tool — the alphabet attacking ideographic writing, the printing press attacking the illuminated manuscript, the photograph attacking the art of painting, television attacking the printed word. When media make war against each other, it is a case of world-views in collision.