: I have learned that neither kindness or cruelty by themselves, or independent of each other, create any effect beyond themselves.

-Albee, Edward Franklin, III
  JERRY1958  The Zoo Story.

Hanging is too good for him, said Mr Cruelty.

-Bunyan,John
  The Pilgrim's Progress, pt1.

Cruelty is the law pervading all nature and society; and we can't get out of it if we would!

-Hardy,Thomas
  Jude the Obscure, pt.5, ch.8.

The Europeans have scarcely visited any coast, but to gratify avarice, and extend corruption; to arrogate dominion without right, and practice cruelty without incentive† But there isreason to hope†that the light of the gospel will at last illuminate the sands of Africa, and the deserts of America, though its progress cannot but be slow when it is so much obstructed by the lives of Christians.

-Johnson, Samuel known as Dr Johnson
  Introduction to The World Displayed.

   Then let us have our libertyagain, And challenge to yourselves no sovereignty. You came not in the world without our pain, Make that a bar against your cruelty; Your fault being greater, why should you disdain Our being your equals, free from tyranny?

-Lanyer, Aemilia
Salve Deus Ex Judaeorum,'Eve's  Apology in Defense of Women'.

La cruaute¤  , bien loin d'e"  tre un vice, est le premier sentiment qu'imprime en nous la nature; l'enfant brise son hochet, mord le te¤  ton de sa nourrice, e¤  trangle son oiseau, bien avant que d'avoir l'a"  ge de raison. Far from being a vice, cruelty is the primary feeling that nature imprints in us. The infant breaks its rattle, bites its nurse's nipple, and strangles a bird, well before reaching the age of reason.

-Sade, Donatien Alphonse Fran c° ois, Marquis de
  La Philosophie dans le boudoir.