“Why bless my soul!” cried Fred, “who’s that?”
“It’s I. Your uncle Scrooge. I have come to dinner. Will you let me in, Fred?”
What strikes the reader immediately is the familial bond which Scrooge calls upon (“Uncle”) to signal his contrition to Fred. After the previous day’s meeting, Fred immediately picks up on the reference and signals his willingness to entertain his uncle.
Family was important to Dickens. And he knew it was just as important to his readers, and to the story. As Mamie Dickens later recalled, “On Christmas Day we all had our glasses filled, and then my father, raising his, would say: ‘Here’s to us all. God bless us!’ a toast which was rapidly and willingly drunk. His conversation, as may be imagined, was often extremely humorous, and I have seen the servants, who were waiting at table, convulsed often with laughter at his droll remarks and stories. Now, as I recall these gatherings, my sight grows blurred with the tears that rise to my eyes. But I love to remember them, and to see, if only in memory, my father at his own table, surrounded by his own family and friends— a beautiful Christmas spirit.”
Also, this scene, real or imagined, was a symbolic gesture then to his brother Fred, with whom he was slowly becoming estranged. This was symbolic of his own personal life, painful as it was, that he would not see his own brother at Christmas.