Why does Scrooge fear the Ghost of Christmas Yet to to come

Having peered into his own empty soul through the first two ghosts, Scrooge fears what his final fate will be.

Ghost of the Future!" he exclaimed, "I fear you more than any spectre I have seen. But as I know your purpose is to do me good, and as I hope to live to be another man from what I was, I am prepared to bear you company, and do it with a thankful heart. Will you not speak to me?"