What lesson did Scrooge learn from each spirit?
In general, Ebenezer Scrooge learned the same lesson from the three spirits. From all of them, he learned that he needed to turn his life around and be a happier, more caring person than he was at the beginning of the story. Each spirit taught him a different part of that lesson.
The first spirit shows him that he (Scrooge) used to be a much happier person. This shows him that it is possible for him to be that way again. This spirit also shows him how important it is to be kind because of the impacts that has on others.
The second spirit shows him that he is now something of a tyrant and that his behavior makes problems for other people. It also shows him that people can be happy without having as much money as Scrooge wants to have.
The third spirit shows him what will happen if he doesn't change his ways. It shows him that his current behavior makes it so that no one loves him or even cares about him.
Between them, the three teach Scrooge that it is important to act more kindly and humanely towards other people (and even towards himself).
Mr Scrooge was living a life of misery without even being aware just how awful he really was in "A Christmas Carol." Inorder to help Mr. Scrooge to betetr understand his need to change he is visited by three spirits.
The first spirit takes him on a journey into his past. He sees himself as a child and he is happy. He remembers what it was like to have been a joyous young man with hopes and dreams. He learns what is missing in his life.
The second spirit is Christmas present. He takes Scrooge to see how other people act and speak of him. He shows Scrooge the love that the Cratchets have for one another despite having no money. He also sees their need for help for their son, Tiny Tim. Scrooge learns to see the balance between money and family.
The third ghost shows Scrooge all the non-blessings his choices have allotted him upon his death. He is not missed nor mourned by others. Instead, they express relief and joy at his death. He died alone and miserable. In contrast is Tiny Tim's death. The boy is missed and longed for by his family. Scrooge learns that if he does not change he will be the miserable man in the casket who no one loves or cares about.
Overall the three spirits teach Scrooge to be a better man.