Oliver Twist is a novel teeming with many closely interrelated ideas. There is preoccupation with the miseries of poverty and the spread of its degrading effects through society. With poverty comes hunger, another theme that is raised throughout the book, along with Dickens's notion that a misguided approach to the issues of poverty and homelessness brings many evils in its wake.
One of the worse consequences of poverty and being deprived of life's essentials is crime, with all of its corrosive effects on human nature. Dickens gives a great deal of attention to the painful alienation from society suffered by the criminal, who may come to feel completely isolated as the fragile foundations of his own hostile world snap. Crime is bad enough in itself, Dickens seems to be saying. When crime is the result of poverty, it completely dehumanizes society.
On the positive side, Dickens places heavy value on the elevating influence of a wholesome environment. He emphasizes the power of benevolence to overcome depravity. And goodness — like criminal intent — may expect to earn its own suitable reward. Sound familiar? The Dickensian theme of virtue being its own reward has its roots in the novels and poems of chivalry and redemption, where the good prosper and the "wicked" are sent packing.