Why were characters from the past brought before Ebenezer Scrooge in A Christmas Carol by Charles Dickens?

In A Christmas Carol, author Charles Dickens writes about miserly old Ebenezer Scrooge, who says, "Bah humbug," whenever Christmas is mentioned. To save Scrooge's miserable life, his deceased partner, Jacob Marley, visits Scrooge with a warning and a message that he will soon be visited by three spirits. The first spirit is the Ghost of Christmas Past, who takes Scrooge on a journey of his personal past. Scrooge sees people and events from his past, and they remind him of what once was. He sees himself as a boy--a boy filled with imagination. He sees his sister, Fan, who he had loved so dearly. He sees his former mentor, Fezziwig, who had taught him much and treated him so well. He sees Belle, the girl he loved and would have married if money had not become such an obsession. All of this was done to help Scrooge realize how wonderful and satisfying life could be. The people he loved were generous and kind-hearted. All of the money in the world could not bring happiness the way trusting, loving relationships do. Scrooge needed to see himself through the eyes of the past in order to change, and this is done effectively with the first Ghost.