Stave four- What is the lesson Scrooge learns in this stave that he had not learned before? Why is this stave needed when Scrooge’s attitude had already changed so much?

In Stave 4, Scrooge learns the truth about the value of his life as it applies to other people. He learns that he is only valued by others if he gives back to mankind. He learns the people that he mistreats like Bob Cratchit are the people that care enough to think of him at Christmas. This stave is needed for Scrooge's final attitude adjustment and his entry into dynamic character status. He sees what his fate will be if he does not change.