The morning after the mob scene, Scout remarks that she thought Mr. Cunningham was a friend of theirs. Atticus remarks that he still is a friend of theirs.
"Mr. Cunningham is basically a good man, he just has his blind spots along with the rest of us" (pg 157)
Atticus then tries to explain that a mob is always made up of people.
"Every mob in every Southern town is always made up of people you know" (pg 157)
Mr. Cunningham had gotten involved in a mob mentality, but he was still a human being. He didn't respond to Scout initially because he was so wound up with the mob. It took an eight-year-old child to make him see that what he was doing was wrong.
"....you children made Walter Cunningham stand in my shoes for a minute. That was enough." (pg 157)
Scout told Mr. Cunningham that night that she knew he was having problems with "entailments" but that Atticus said not to worry about it because ".....you'd all ride it out together." (pg 154). It made Walter Cunningham realize that Atticus would "ride it out" with Tom Robinson also. Atticus believes
"That proves something----- that a gang of wild animals can be stopped, simply because they're still human" (pg 157)
Once Scout makes him realize what he is doing is wrong, he leaves and pulls the rest of the men with him.
Atticus explains to Scout that it took an eight year old girl to move them. When Scout told Mr. Cunningham that she knew his son and asked him to tell Abraham that she said "hey"-he realized that what he and the others were doing was not right. Once he finally understood that he never should have acted so hastily-Mr.Cunningham stated,"I'll tell him you said hey, little lady" and with a simple gesture-he told the other men to go home. So it was Scout that brought the mob to their senses.