Mr. Cunningham seemed to Scout to be the leader of the mob the night before. She remarks to Atticus the next morning that she thought Mr. Cunningham was a friend of theirs. Atticus remarks that he is a friend of theirs. Basically Mr. Cunningham was a good man, but he has blind spots that everyone seems to have. He explains that a mob is always made up of people. He tells the children that
"Every mob in every little Southern town is always made up of people you know -----doesn't say much for them, does it? " (pg 157)
He was impressed with what Scout said and did the night before. He says that it shows that...
"a gang of wild animals can be stopped simply because they're still human" (pg 157)