ghost of christmas yet to come

Question 1

The phantom slowly, gravely, silently approached

Answer 1

The final ghost resembles the Grim Reaper and human’s fear of death. It cannot speak just as the future cannot speak for us but can reveal what could happen. Scrooge must now lead his final stage of redemption - his humility shows he wants to learn.
Structurally it appears at the end of Stave 3 as speed builds towards Scrooge’s final redemption.

Question 2

‘Ghost of the future!’ he exclaimed. ‘I fear you more than any Spectre I have seen. But… I know your purpose is to do me good.’

Answer 2

Scrooge is willing to see what it takes for him to be a changed man