What did the ghost of Marley tell Scrooge in A Christmas Carol by Charles Dickens?

In the first stave of A Christmas Carol, the ghost of Jacob Marley visits Scrooge. The purpose of his visit is to warn Scrooge of some impending visitors, as Marley explains,

"You will be haunted,'' resumed the Ghost, "by Three Spirits.''

According to Marley, the first spirit will appear the next night "when the bell tolls one." The second will come at the same time on the next evening. The evening after that, the third spirit will visit just after the clock strikes twelve.

The purpose of these visits is to ensure Scrooge does not experience the same fate as Marley, who is now carrying out "penance" in the afterlife. It is to demonstrate to Scrooge that the business of "charity, mercy, forbearance, and benevolence" are far more important than the financial business conducted in the counting-house. In other words, the visits seek to reform Scrooge's character before it is too late and he is forced to wander the world in the afterlife, just like Marley must.