It's Elijah's job to go and collect the mail for the inhabitants of Buxton. Not only that, but he reads letters to Mrs. Holton, who's illiterate. On this particular occasion, Mrs. Holton has received some particularly bad news; her husband John, who was a slave, has been beaten to death by his owners.
Such atrocities were common at that time, and all too many slaves suffered an identical fate at the hands of their owners and slave masters. Yet that in no way minimizes the shock and devastation that Mrs. Holton must be feeling upon hearing the terrible news about her husband.
Even before Elijah reads the letter to Mrs. Holton, he, with everyone else in the settlement, knows that it brings bad tidings. Experience has taught everyone that when someone receives a letter from America, it's always bad news. When Elijah heads off to read Mrs. Holton her letter, he is accompanied by his Ma and a number of other people. By the time they reach her house, there are twelve of them in total.
All the adults present want to rally round Mrs. Holton and show their support for her at what they know will be a very difficult time. They cannot change what's happened to John, but they can at least let Mrs. Holton know that they're thinking of her and that they stand with her in her hour of darkness.