Why is stave 4 in 'A Christmas Carol' needed when Scrooge's attitude had already changed so much?
"Stave IV" is the nail in Scrooge's coffin; it makes certain that Scrooge's change is permanent, for in it he sees his demise in the form of his grave which is described as
overrun by grass and weeds, the growth of vegetation's death, not life; choked up with too much burying; fat with repleted appetite!
Upon looking at his "neglected grave" and seeing his own name engraved upon the tombstone, Scrooge makes the verbal commitment to always
honour Christmas in [his] heart, and try to keep it all the year. [He] will live in the Past, the Present, and the Future.
In this passage, we see that the element of human time is completed, for without seeing the future, Scrooge could not fully accept his change, for not only does he see his own future, but he also sees the future of Tiny Tim, who reminds Scrooge of his past self.
What Dickens is revealing is just how important the past, present and future are, not only to Scrooge but to the reader. What happens in the past, and what happens in the present, surely affect the future, so to complete Scrooge's metamorphosis he has to see his future. Scrooge clearly sees that he is heading to hell, and by the time he sees this, the Present and Past have awakened what is good in Scrooge's soul so that he fears the finale.
I'm afraid poor old Scrooge has a lot more character transformation to endure before he can truly be a changed and joyful man from the true bottom of his heart in the short novella A Christmas Carol by Charles Dickens. It is one thing to have your shortcomings as a human being explained to you but quite another to take them on board, to 'own' your mistakes and then, through an epiphany of the soul, use that new2 knowledge to actually physically change things next time. It is not enough for Scrooge to see the damage of the past, he needs to be shown and foresee where all is going to take him, and humanity , in the future. Only then can he accept responibilty and blame and see cause and effect.