What is Atticus’ response to Mr. Ewell’s actions?

Bob Ewell was angry with Atticus after the trial.  One day, Atticus went to the Maycomb post office.  After he left, he ran into Mr. Ewell outside.  It was then that Bob Ewell "spat in his face, and told him he'd get him if it took the rest of his life" (To Kill a Mockingbird, Chapter 22).  Mr. Ewell proceeded to yell and curse.  He accused Atticus of being too proud to fight back.  

Atticus was not upset or afraid by the incident.  He wiped the spit off his face, and later mentioned that he wished Bob Ewell was not a tobacco chewer.  Jem later asked his father about the incident.  Atticus calmly told his son to consider walking in Bob Ewell's shoes.  At the trial, Atticus had "destroyed his last shred of credibility at that trial, if he had any to begin with" (Chapter 23).  He noted that Mr. Ewell was going to take out his anger on someone.  He preferred for it to be on him rather than on one of his children.