With reasonable men, I will reason; with humane men I will plead; but to tyrants I will give no quarter, nor waste arguments where they will certainly be lost.

From William Lloyd Garrison, 1805-1879: The Story of His Life Told by His Children, 1885 by Wendell Phillips Garrison and Francis Jackson Garrison.  Garrison was a famous journalist and abolitionist.  

Wherever there is a human being, I see God-given rights inherent in that being, whatever may be the sex or complexion.

And

With reasonable men, I will reason; with humane men I will plead; but to tyrants I will give no quarter, nor waste arguments where they will certainly be lost.