Determine the author’s main purpose in the following passage from Huckleberry Finn, by Mark Twain, in which Huckleberry Finn confronts his dilemma over turning in the runaway slave, Jim:

I got to thinking over our trip down the river, but somehow I couldn’t seem to strike no places to harden me against him, but only the other kind. At last I struck the time I saved him by telling the men we had smallpox aboard, and he was so grateful and said I was the best friend old Jim ever had in the world…I was a-trembling because I’d got to decide forever betwixt two things, and I knowed it. I studied a minute, sort of holding my breath, then says to myself, “All right, then. I’ll never turn him in. I’ll go to hell.”