“In an age when nations and individuals routinely exchange murder for murder, when the healing grace of authentic spirituality is usurped by the divisive politics of religious organization, and when broken hearts bleed pain in darkness without the relief of compassion, the voice of an exceptional poet producing exceptional work is not something the world can afford to dismiss.”

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 579.

1960s, Where Do We Go from Here: Chaos or Community? (1967)
Context: I say to you today that I still stand by nonviolence. And I am still convinced that it is the most potent weapon available to the Negro in his struggle for justice in this country. And the other thing is that I am concerned about a better world. I'm concerned about justice. I'm concerned about brotherhood. I'm concerned about truth. And when one is concerned about these, he can never advocate violence. For through violence you may murder a murderer but you can't murder murder. Through violence you may murder a liar but you can't establish truth. Through violence you may murder a hater, but you can't murder hate. Darkness cannot put out darkness. Only light can do that.

Spoken by Assistant District Attorney Jack McCoy in the Law & Order episode Vaya Con Dios.
Law & Order

Psychomagic: The Transformative Power of Shamanic Psychotherapy (2010)

Section 1, member 2, subsection 5.
The Anatomy of Melancholy (1621), Part I

Quoted allegedly "From da Vinci`s Notes" in Jon Wynne-Tyson: The Extended Circle. A Dictionary of Humane Thought. Centaur Press 1985, p. 65 books.google http://books.google.de/books?id=1mMbAQAAIAAJ&q=murder.
Actually the quote is not authentic but made up from a novel by Dmitri Merejkowski (w:Dmitry Merezhkovsky) entitled "The Romance of Leonardo da Vinci" (La Résurrecton de Dieux 1901), translated from Russian into English by Herbert Trench. G.P. Putnam's Sons New York and London, The Knickerbocker Press. There, in Book (i.e. chapter) VI, entitled The Diary of Giovanni Boltraffio, one finds the following:
The master [Leonardo da Vinci] permits harm to no living creatures, not even to plants. Zoroastro http://it.wikipedia.org/wiki/Tommaso_Masini tells me that from an early age he has abjured meat, and says that the time shall come when all men such as he will be content with a vegetable diet, and will think on the murder of animals as now they think on the murder of men ( p. 226 books.google http://books.google.de/books?id=g_pa0OaYX64C&pg=PA226).
However, despite the quote's false attribution, da Vinci was in fact a vegetarian.
Misattributed

Source: Inauguration of a joint project between the government and the Catholic Church, in favor of care and rehabilitation of drug addicts http://fides.org/en/news/18487-america_mexico_Inauguration_of_a_joint_project_between_the_government_and_the_Catholic_Church_in_favor_of_care_and_rehabilitation_of_drug_addicts (27 October 2008)

Page 141
2000s, Promises to Keep (2008)

In Quotations by 60 Greatest Indians, Dhirubhai Ambani Institute of Information and Communication Technology http://resourcecentre.daiict.ac.in/eresources/iresources/quotations.html,