In A Christmas Carol, the three ghosts are sent to Mr. Scrooge by his dead partner Jacob Marley who attempts to save his friend's immortal soul from the torment that he is experiencing. Mr. Marley is desperate to prevent Scrooge from sharing his afterlife of helpless wandering. He tells Scrooge that he must see the error of his ways and change before it is too late. The ghosts give Scrooge an opportunity to look at his life, past, present and future against the backdrop of what Christmas means to different people.
Since Mr. Scrooge is a man who has lost touch with his humanity, and is totally devoted to the pursuit of money, the ghosts serve to confront him with raw human experiences and emotions, in some cases reminding him of what he once felt, in others allowing him to view the celebrations of family that others share.
The Ghost of Christmas brings Scrooge back to his childhood, highlighting the fact that his own father was cruel and indifferent to him because his mother died giving birth to him. It also allows the reader a chance to see why Mr. Scrooge is so bitter and lonely. He looks at his past self, his sister, and remembers that he once loved someone very much.
The Ghost of Christmas Present offers Scrooge a chance to see what he is missing by showing him Fred's celebration with his wife and friends, and he also brings him into the humble home of Bob Crachit, his clerk who earns very little money yet supports his large family with an exuberant love that he shares with his wife and children.
Scrooge gets a chance to see, first hand, the struggle of Tiny Tim, Crachit's little son, who is destined to die at a young age. The sight of the young boy with the crutch moves Scrooge's heart.
The Ghost of Christmas yet to come is a frightening, shrouded figure who is mysterious, just as the future is. This specter shows Scrooge what his material wealth will amount to once he is gone from this earth, and without saying a single word, brings him to his knees with an understanding that the isolation he craves while he is alive will insure a lonely unnoticed death.
The spirits show Scrooge what an empty life he is living; they show him that his money will not protect him from death, nor will his money insure that he will be respected. The only way to live a full life is to surround oneself with people, family, friends, etc.
The spirits provide Mr. Scrooge with a path to redemption. He is saved at the end, Mr. Marley succeeds in saving his friend's soul, and his life. Mr. Scrooge becomes a generous, loving man, sharing his wealth with the needy, embracing his nephew Fred and his wife, and helping Bob Crachit with his large family.