At the beginning of Chapter XXIV, Pip explains what little he knows about what is expected of both him and his tutor Mr. Pocket.
After two or three days, when I had established myself in my room and had gone backwards and forwards to London several times, and had ordered all I wanted of my tradesmen, Mr. Pocket and I had a long talk together. He knew more of my intended career than I knew myself, for he referred to his having been told by Mr. Jaggers that I was not designed for any profession, and that I should be well enough educated for my destiny if I could "hold my own" with the average of young men in prosperous circumstances. I acquiesced, of course, knowing nothing to the contrary.
Matthew Pocket is invented as a character in order to explain how Pip becomes a real gentleman by the time his secret benefactor Magwitch makes his appearance in Chapter XXXIX. Mr. Pocket acts only as a tutor and advisor to Pip, whose education consists largely of reading in the company of Bartley Drummle and Startop as well as reading at home. The fact that Matthew Pocket is related to Miss Havisham increases Pip's belief that Miss Havisham must be his secret benefactor. Mr. Pocket also encourages Pip to go to places that are frequented by young gentlemen so that he can pick up their manners and attitudes. Pip develops bad habits. He learns how to waste time and money, and this is part of his education as a gentleman because he is becoming like all the other young gentlemen of London. Dicken's illustrates Pip's transformation into a gentleman in Chapter XXXIV with a description of the Finches of the Grove.
At Startop's suggestion, we put ourselves down for election into a club called the Finches of the Grove: the object of which institution I have never divined, if it were not that the members should dine expensively once a fortnight, to quarrel among themselves as much as possible after dinner, and to cause six waiters to get drunk on the stairs.
Magwitch is delighted with Pip when he meets him after so many years in Chapter XXXIX. Pip is exactly Magwitch's idea of a London gentleman. He has acquired a lot of book knowledge through desultory reading which has not prepared him for any profession. He had acquired good manners but is completely selfish, wasteful and lazy--just as a gentleman should be in Magwitch's opinion. He is entirely dependent on the money he receives from his unknown benefactor, who, to his utter horror, turns out to the the ignorant and vulgar Abel Magwitch. Mr. Pocket has been the ideal tutor for Pip because Pocket is a gentleman who never acquired any discipline and has ended up earning a living by teaching other men to be like himself. Pocket also earns money to support his large, chaotic family by lecturing on domestic economy. In Chapter XXXIII, Pip writes:
Mr. Pocket was out lecturing; for he was a most delightful lecturer on domestic economy, and his treatises on the management of children and servants were considered the very best text-books on those themes.