Scrooge: '"I don't make merry myself at Christmas, and I can't afford to make idle people merry. I help to support the establishments I have mentioned: they cost enough: and those who are badly off must go there."'
Marley's ghost: '"I wear the chain I forged in life," replied the Ghost. "I made it link by link, and yard by yard; I girded it on of my own free will, and of my own free will I wore it. Is its pattern strange to you?"'
Ghost: '"I see a vacant seat," replied the Ghost, "in the poor chimney corner, and a crutch without an owner, carefully preserved. If these shadows remain unaltered by the Future, the child will die."'
The Ghost of Christmas Present shows Scrooge Ignorance and Want to emphasise that poverty is a cycle - poor children grow up to be desperate adults if they are given no opportunities
When Scrooge's line is quoted back to him by the ghost, Dickens is making it clear that prisons and workhouses don't give the poor any chance to escape that cycle of poverty