Jacob Marley, his late partner.
All the spirits teach scrooge a lesson
The three spirits were the Spirit of Christmas Past, the Spirit of Christmas Present, and the Spirit of Christmas Future.
Jacob Marley's was Ebenezer Scrooge's business partner. He was sent to warn Scrooge to listen and learn from the next three spirits to visit or he will suffer in the afterlife.
To show scrooge issues he encountered in his past
In "A Christmas Carol" by Charles Dickens, Ebenezer Scrooge is visited by four spirits: Marley's ghost, the Ghost of Christmas Past, the Ghost of Christmas Present, and the Ghost of Christmas Yet to Come.
It was the light to help Scrooge see throgh the darkness of his troubled past
Before the spirits visit, Scrooge is a wealthy but miserly and unkind businessman who hoards his money and refuses to help others in need. He is cold-hearted, selfish, and uncompassionate towards those around him.
It ends on the Twelth Night
Marley tells Scrooge to expect three more spirits to visit him that night.
Charles Dickens likely presented the spirits in time order in "A Christmas Carol" to show Scrooge the progression and impact of his past, present, and future actions. By leading Scrooge through his life in this structured way, Dickens emphasized the importance of reflecting on one's choices and their long-term consequences. This approach also allowed Scrooge to witness the growth and change that can occur over time, encouraging him to make positive changes in the present.
They taught him to be kind to people and not to be selfish
The light was there to show Scrooge shadows of his past. When he did extinguish that flame the scenes were over and Scrooge was once more in his bed