Mankind was my business
Jacob Marley, and the chain he forged in life
Marley is on stage for about ten minutes and he is the most frightening thing Dickens ever wrote, for a reason that has nothing to do with being a ghost.
He is not being punished for cruelty. He was not cruel. He was a reasonably successful businessman who attended to business, and the horror is that this turns out to have been the wrong business entirely.
"Mankind was my business. The common welfare was my business; charity, mercy, forbearance, and benevolence, were, all, my business. The dealings of my trade were but a drop of water in the comprehensive ocean of my business!"
The chain is the good part
He made it himself, link by link, and never noticed:
"I wear the chain I forged in life. 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."
Nothing in the novel is as unsettling as that. There is no moment of damnation, no bargain, no decision anyone would recognize as a mistake while making it. Just a long accumulation of ordinary days that each seemed reasonable.
And Scrooge's chain, Marley tells him, is already far longer.
Why this is the line that survives rereading
"Bah humbug" is a joke you have known since childhood. Marley's speech is the one that changes depending on how old you are when you read it.
At twenty it is a ghost story. At forty it is a question about what you have been treating as your actual business for the last decade — and the fact that Dickens puts it in the mouth of a man who cannot do anything about it anymore is the whole point.
He is not there to haunt Scrooge. He is there because he is the only one who can still be warned about.
The lines worth having on a wall:
Questions people ask
What does 'mankind was my business' mean?
Marley's realization that the work he spent his life on was not his real work. Trade, he says, was 'a drop of water in the comprehensive ocean' of what should have occupied him.
What is Marley's chain made of?
Cash boxes, keys, padlocks, ledgers, deeds and heavy purses — the instruments of his trade. He forged it himself, link by link, without noticing.
Why is Marley more frightening than the three ghosts?
Because he did nothing anyone would recognize as evil. He attended to business. The horror is that an ordinary, reasonable life accumulated into the chain.