But somehow I couldn’t seem to strike no places to harden me against him, but only the other kind. I’d see him standing my watch on top of his’n, ‘stead of calling me, so I could go on sleeping; and see him how glad he was when I come back out of the fog; and when I come to him again in the swamp, up there where the feud was; and such-like times; and would always call me honey, and pet me and do everything he could think of for me, and how good he always was; and at last I struck the time I saved him by telling the men we had small-pox aboard, and he was so grateful, and said I was the best friend old Jim ever had in the world, and the ONLY one he’s got now; and then I happened to look around and see that paper.

– Mark Twain

The Adventures of Huckleberry Finn, Chapter 31. Huck agonizes over whether he should turn in the fugitive slave Jim, as society’s rules demand he should. He tries to come up with something that will “harden” him against the runaway. But his bond of friendship with Jim is so strong and deep, he cannot.