Obviously poverty is bad. It's poverty that leaves David isolated and without a future as a child laborer in London. And in David Copperfield, charitable institutions are bad. It's a charitable school that twists Uriah Heep into a vengeful monster. Wealth, in this novel, is also bad. It leaves people selfish and unfeeling, like Steerforth. In the world of this book, the only way for an honorable man to cope with poverty is to sacrifice long hours of his life to honest, professional toil: this is the path that both David and Traddles choose. Yet, at the same time, the characters who are allowed to work their way out of poverty are relatively few. It's only the sons of gentlemen – people who are born into the English middle class – who can follow David's path. The working-class characters like Mr. Peggotty and Ham Peggotty are virtuous in part because they don't upset the social order. It seems to us that, even though David gets his rags-to-riches story, the class system in David Copperfield is still pretty rigid.
The Peggotty family is the only poor but happy family in the novel because they are working class and expect to remain so. Emily suffers more than the rest of her family because she wants to join a higher social class.
David Copperfield sets out to teach its readers that, to climb out of poverty, you must have David's virtues of hard work, dedication, and loyalty.