In the very opening paragraph of Charles Dickens’ A Christmas Carol, the narrator begins as follows:
Marley was dead: to begin with. There is no doubt whatever about that. The register of his burial was signed by the clergyman, the clerk, the undertaker, and the chief mourner. Scrooge signed it: and Scrooge’s name was good upon ’Change, for anything he chose to put his hand to. Old Marley was as dead as a door-nail.
The phrase stating that “Scrooge’s name was good upon ’Change” means that Scrooge had good financial credit at the Royal Exchange in London, the most important of England’s financial institutions. By extension, the phrase means that Scrooge’s word was considered reliable; he was considered a trustworthy, honorable man. Anything he signed (such as a contract) was taken seriously. Therefore, if Scrooge was willing to sign a document testifying to the death of Marley, Marley surely was dead, and no one could reasonably doubt this fact.
The irony, of course, is that later in the story Marley will seem to come back to life and will seem to visit the very Scrooge who is so sure that his friend is deceased. A further irony is that as a result of Marley’s visit, Scrooge – who is himself leading a kind of dead and deading life – will be revived and restored to a much more vital existence than he is presently enduring.