““War!”
The thought stood in Sim’s brain. It shocked and beat at him. These men were running to fight, to kill, over there in those small black cliffs where other people lived.
But why? Wasn’t life short enough without fighting and killing?”

Men
Lyrics

As quoted in May I Quote You, General Forrest? by Randall Bedwell.
1860s

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. ]

Source: Lady Midnight

"The Pacifist"
Sonnets and Verse (1938)

"Reunion in Brooklyn" http://books.google.com/books?id=uzz94pR0VQsC&q=%22To+live+without+killing+is+a+thought+which+could+electrify+the+world+if+men+were+only+capable+of+staying+awake+long+enough+to+let+the+idea+soak+in%22&pg=PA131#v=onepage, Sunday After the War (1944)

Empire of Dreams (prose poetry, 1988)

Preface to Hermetical Physick of Henry Nollus (1655).