When did the Ghost of Christmas Present use Scrooge's own words against him?

The Ghost of Christmas Present is trying to convey to Scrooge—as Dickens is to his audience—that words have meaning. When Scrooge brushes off the charitable requests and impulses of people asking him for help on Christmas Eve, what he says are just words to him. When he states it would be better for the poor to die and rid England of its excess population or go to prisons or workhouses, "the poor" are simply an abstraction in his mind. He is simply mouthing sentiments, hard-hearted as they are, that he has heard others express. He can't really imagine what it is to truly be in need.
But when Scrooge sees real poor people, like Cratchits, and especially Tiny Tim, his attitude changes. "The poor" are now not simply a disposable category, but real people like him with hearts and personalities and minds that are worth preserving. Having really seen the Cratchits for the first time, their struggles and sorrows become of great concern to him and can no longer be dismissed. The thought of Tiny Tim dying for no more reason than lack a little money for medical care fills Scrooge with grief. Even the poor children Ignorance and Want under the ghost's robes become objects of his compassion as is heart is awakened and stirred.
Dickens has the ghost throw Scrooge's words back at him, because he wants us to make a connection between callous words and real people. The hard-hearted way we speak of "the poor" ignores the fact that these are suffering people. Today, we might simply say "get a job" or "why don't they get a job?" or "Why should they get food stamps?" when the reality is, if we knew one or two of "these people" personally, we would probably feel much more compassion. In the end, Dickens believed, it was the role of the novelist (like the role of the Ghosts—and what is a novelist but a ghostly presence from "another world?") to put the flesh and blood on mere words so that they became attached to people and feelings.

In Stave Three, the Ghost of Christmas Present turns Scrooge's words against him on two occasions. The first of these occurs when the ghost and Scrooge are visiting the Cratchit family. On the subject of Tiny Tim, Scrooge asks the ghost if he thinks that Tim will survive. In response, the ghost says he sees a vacant seat at the dinner table next Christmas. It is at this point that the ghost uses Scrooge's words against him:

 "'What then? If he be like to die, he had better do it, and decrease the surplus population.'''

The second occasion occurs after Scrooge sees Ignorance and Want hiding underneath the ghost's robes. When Scrooge asks if there are any resources available to help these children, the ghost repeats Scrooge's words from Stave One:

"'Are there no prisons?'' said the Spirit, turning on him for the last time with his own words. 'Are there no workhouses?'"

By using Scrooge's words against him, the ghost highlights Scrooge's negative attitude towards the poor while also providing an impetus for change.