The ever-optimisic Atticus believes Bob Ewell has once and for all settled the score when he spits in Atticus's face and threatens to kill him.
"We don't have anything to fear from Bob Ewell, he got it all out of his system that morning." (Chapter 23)
When Bob spits, curses, threatens and then tries to force Atticus to fight, Atticus merely wipes the spittle away and walks off, telling Bob that he is "too old" to fight. His only complaint is that
"I wish Bob Ewell wouldn't chew tobacco..." (Chapter 23)
Atticus uses the occasion to remind Jem to "stand in Bob Ewell's shoes a minute." Atticus explains that Bob had little choice but to "have some kind of comeback," and Atticus doesn't mind being the recipient of Bob's anger if it
"... saved Mayella Ewell from one extra beating, that's something I'll gladly take... I'd rather it be me than that household of children out there." (Chapter 23)
Of course, Atticus's family doesn't agree. Scout thinks Atticus should pack a gun, and Alexandra believes Bob is still capable of "something furtive."