Why have the neighbors gathered in the Finch's front yard?

In Chapter 15, a group of men pay a call to Atticus at his home. Jem and Scout watch from inside. The men make allusions to Tom being moved to the Maycomb jail the next day (Sunday), because the trial will occur on Monday. They are concerned that the "Sarum bunch" will cause some trouble, but Atticus thinks they won't do anything (such as a lynching) on a Sunday night. Mr. Link Deas warns Atticus that he has everything to lose from the trial, but Atticus says that he wants the truth to come out. Jem is concerned that the men outside mean Atticus harm, but Atticus assures him later that those men are his friends and are not part of a gang or the Ku Klux Klan, whom Atticus claims is gone and will never come back.