Pip's autobiography is an implicit criticism of the class system in England. He wants to become a gentleman without understanding what that term actually means. All he sees from his lower-class perspective is fine clothes and fine manners. When he does succeed in becoming a gentleman he realizes that he has become a useless parasite and a fop. His meeting with Abel Magwitch in Chapter 39 is an almost surrealistic revelation to Pip of what it really means to be a gentleman. It means enjoying a life of leisure and privilege at the expense of the suffering of others. Poor Magwitch does not realize that in creating "his own" gentleman he has succeeded in creating someone who looks, talks, and acts impressively but is really worthless as a human being.
I says to myself, 'If I ain't a gentleman, nor yet ain't got no learning, I'm the owner of such. All on you owns stock and land; which on you owns a brought-up London gentleman?'
The relationship between Pip and Magwitch symbolizes that which existed between the upper and lower classes. The fine ladies and gentlemen were unaware that their comfortable lifestyle was based on exploitation of those who did all the world's labor. And the working class admired those who enjoyed luxuries without ever getting their hands dirty, not realizing that it was they themselves who were making such a leisure-class existence possible. Dickens' entire novel is intended to illustrate that truth--but it is only Pip who realizes how he is figuratively chained to the convict who made him a gentleman without understanding what a gentleman was and what sort of a helpless, dependent wretch he was creating..
“Look'ee here!” he went on, taking my watch out of my pocket and turning towards him a ring on my finger, while I recoiled from his touch as if he had been a snake, “a gold 'un and a beauty: that's a gentleman's, I hope! A diamond all set round with rubies; that's a gentleman's, I hope! Look at your linen; fine and beautiful! Look at your clothes; better ain't to be got!”