Oliver Twist is undoubtedly a moral novel in which good triumphs over evil. Considering the philosophies and behaviors of both the good and evil characters in the story, its main moral message is arguably the importance of compassion and community in forming individuals.
Compassion is sorely lacking in Oliver's society. The poor are treated as lazy dogs unfit for any charity. Simply due to lacking parents or money, Oliver is told again and again that he is destined to become a victim of the gallows. As a result, poor children such as himself are often forced into a criminal life, creating a self-fulfilling prophecy. At the time Dickens wrote the novel, such attitudes were common, leading to the unjust Poor Law of 1834, which essentially punished people for needing government assistance. By showing how Oliver and other characters are affected by these prejudices, Dickens is emphasizing the need for compassion should anyone want the situation of the needy to improve.
Throughout the book, characters are also highly affected by their surroundings. With the exception of the guileless Oliver (presented slightly as a tabula rasa in danger of becoming corrupted by bad company), the morally good characters tend to come from loving families and support systems while the evil characters act wholly from self-interest. The criminals in Oliver Twist—both the underworld types like Fagin and Bill and the underhanded likes of Mr. Bumble and Mrs. Corney—are driven by selfishness. While they do form communities, they are not lasting ones, nor are they built on unconditional love. Fagin keeps his young orphans in his care so long as they can procure him stolen goods, and Mr. Bumble only courts Mrs. Corney because he covets her possessions. By having both lawbreakers and so-called lawful types exhibiting such behavior, Dickens is illustrating that this behavior is not limited to the poor, challenging the assumptions of his original audiences.
Dickens makes it plain that redemption and goodness are possible for all people regardless of class, as are corruption and lawlessness. He openly contrasts the characters of Nancy, the prostitute and pickpocket, and Rose Maylie, the virtuous young lady: Nancy was raised in a world of criminal self-interest and exploitation, while Rose was raised in a loving family. Dickens subtly suggests that one could have easily become like the other had she been brought up within a different community. That Nancy is able to redeem herself morally by saving Oliver from her fate is Dickens' ultimate illustration of his moral message: no one is inherently evil, and compassion can go a long way in building a better society.