"Business!.. Mankind was my business. The common welfare was my business; charity, mercy, forbearance, and benevolence were all my business." (Stave I, 628)
"Say that his power lies in words and looks; in things so slight and insignificant that it is impossible to add and count 'em up: What then? The happiness he gives us is as great as if it cost a fortune." (Stave II, 637)
The theme of The Christmas Carol is to be kind and benevolent and make others happy, as happiness costs no money.
"Will you decide what men should live, what men shall die? It may be that, in the sight of Heaven, you are more worthless and unfit to live than millions like this poor man's child." (Stave III, 649)
This helps develop the theme of kindness and generosity because it shows Jacob Marley lamenting over how he did not live by these values in life. This encounter acts as an incentive for Scrooge and sets the ground work for establishing the theme of the text.
"I will honor Christmas in my heart, and try to keep it throughout the year. I will live in the Past, the Present, and the Future. The Spirits of all Three shall strive within me. I will not shun out the lessons they teach." (Stave IV, 663)
This helps develop the theme that happiness costs nothing, spreading joy costs nothing. This shows Fezziwig's party and how Scrooge defends him, saying how even though Fezziwig spent very little money, the good cheer he caused made him great. Then Scrooge realizes the hypocrisy in what he just said, and thinks about how he could be different. This in turn helps develop the theme of the story.
This helps develop the theme because this shows Scrooge the wrongness in his ways, and how being kind and generous will benefit everyone, and being selfish and cruel will benefit no one.
This scene shows Scrooge promising to change his ways. He is swearing to keep the Christmas spirit, that is, to be kind and benevolent, solidifying the theme.