Miss Stephanie is the town gossip.  Early in the chapter she approaches the children with the rumors that were circulating around town about their presence in the balcony with the colored folks.  Miss Maudie tries to rescue the children with an offer of cake and takes them away from Miss Stephanie.  While the children are visiting Miss Maudie, Miss Stephanie continues her gossip with Mr. Avery.  They move a little further down the sidewalk.  Suddenly Miss Rachel, Dill's aunt, joins them, and Aunt Alexandra calls the children to come home.  However, it is too late.  Miss Stephanie tells them that Bob Ewell stopped Atticus at the post office corner, spat in his face, and told him that he would get back at him for what Atticus did to him at the trial if it took him the rest of his life. In the next chapter, the story gets more detailed.

"According to Miss Stephanie, Atticus was leaving the post office when Mr. Ewell apraoched him, cursed him, spat on him, and threatened to kill him......Miss Stephanie said Atticus didn't bat an eye; just took out his handkercheif and wiped his face and stood there and let Mr. Ewell call him names wild horses could not bring her to repeat." (pg 217- chapter 24)  

Atticus tells the children,

"Jem, see if you can stand in Bob Ewell's shoes a minute.  I destroyed his last shred of credibility at that trial, if he had any to begin with.  The man had to have some kind of comeback." (pg 218-chapter 23)

Atticus is very good at taking situations like these and teaching the children how to react to human behavior.  One of his basic lessons in the book is to put yourself in another's shoes before you pass judgement on them.