This is the beginning of a comic-book story in which a "hood" teaches two little boys: "If you kids wanna learn to be like me, you gotta be tough! Never give the other guys an even break!"
He shows them a well-dressed young boy. They proceed to threaten this boy and he hands over his money to them. But that does not satisfy the tough teacher. He bangs their heads together and exclaims: "You always have to slug 'em! Remember that!" This is the elementary lesson of crime comics.