Interestingly, Dickens intentionally created Oliver as a character who is not influenced by anything. Throughout the book, Oliver is "tempted" by various characters, who try to teach him how to live a life of crime. Oliver does not really understand what they really are. He sees Fagin as a kindly benefactor and the boys as young gentlemen who are kind to him. Oliver is naive enough to believe what Fagin tells him. In chapter 9, the boys bring pocketbooks that they have pickpocketed.
“Not so heavy as they might be,' said the Jew, after looking at the insides carefully; 'but very neat and nicely made. Ingenious workman, ain't he, Oliver?”
As with the handkerchiefs that Fagin tells him they have just put them out “ready for the wash” (chapter 9), Fagin tells Oliver that the boys are learning to make wallets. Oliver does not realize or understand that the boys are really stealing handkerchiefs and pocketbooks that they bring back to Fagin.
Oliver doesn’t understand the importance of the game. When Fagin teaches him how to pick his pockets, he doesn’t understand that he is going to be asked to go out and rob people.
“Oliver wondered what picking the old gentleman's pocket in play, had to do with his chances of being a great man. But, thinking that the Jew, being so much his senior, must know best, he followed him quietly to the table, and was soon deeply involved in his new study.” (chapter 9)
Oliver assumes that Fagin knows best because he is older, and Oliver has never had good role models. Interestingly enough, Nancy turns out to be a positive influence in Oliver’s life. When he first meets her, he thinks she is not quite pretty but is happy and charming. Oliver is surprised when Nancy turns up to take him back to Fagin. When Fagin starts to beat Oliver with a club, Nancy intervenes.
Fagin and Sikes try to bring Nancy down a peg, reminding her who she is and telling her that she is “a pretty subject for the child, as you call him, to make a friend of!” (chapter 16). Nancy regrets returning Oliver, though she had no choice. She tells Fagin and Bill:
“He's a thief, a liar, a devil, all that's bad, from this night forth. Isn't that enough for the old wretch, without blows?”
Nancy’s predictions do not come true because she manages to warn Rose and Brownlow that Oliver is not the boy they think he is, and it is through Nancy’s intervention that they find out that Oliver is Rose’s nephew. Nancy risks her life, and in fact gives her life, to keep Oliver honest and innocent.