“Well, dey’s reasons. But you wouldn’ tell on me ef I uz to tell you, would you, Huck?”
“Blamed if I would, Jim.”
“Well, I b’lieve you, Huck. I – I RUN OFF.”
“But mind, you said you wouldn’ tell – you know you said you wouldn’ tell, Huck.”
“Well, I did. I said I wouldn’t, and I’ll stick to it. Honest INJUN, I will. People would call me a low-down Abolitionist and despise me for keeping mum – but that don’t make no difference. I ain’t a-going to tell, and I ain’t a-going back there, anyways. So, now, le’s know all about it.”

– Mark Twain

The Adventures of Huckleberry Finn, Chapter 8. Huck is shocked that the Jim has run off. But he assures the runaway slave that he will keep his word about not telling on him. To Huck honoring his word to Jim appears more important than his own reputation, and even abiding by the law. Huck likes to defy society’s rules. Abolitionist is an allusion to abolitionism, the movement to end slavery.