What was there to be gained by fighting the most evil wizard who has ever existed?" said Black, with a terrible fury in his face. "Only innocent lives, Peter!""You don't understand!" whined Pettigrew. "He would have killed me, Sirius!""THEN YOU SHOULD HAVE DIED!" roared Black. "DIED RATHER THAN BETRAY YOUR FRIENDS, AS WE WOULD HAVE DONE FOR YOU!
J.K. Rowling, Harry Potter and the Prisoner of Azkaban
betrayal, friends, traitor, treachery