I heard a muttered curse and got slugged again, and they were stuffing a handkerchief in my mouth. (1.16)
The handkerchief is such a creepy detail. The Socs try to quiet Pony in this way almost as a reflex. It tells us that they're experienced in violent assault, and suggests that the activity makes up a big part of their lives. Yick.
I had never been jumped, but I had seen Johnny after the after four Socs got hold of him, and it wasn't pretty. Johnny was scared of his own shadow after that. He was sixteen then. (1.7)
Later in the novel, Johnny gives Cherry a more detailed description of Johnny's beating, and it's really hard to read. The Outsiders is very clear that the violence is serious and real.
Greasers can't walk alone too much or they'll get jumped, or someone will come by and scream "Greaser!" at them which doesn't make you feel too hot if you know what I mean. (1.4)
In this early passage Pony describes the physical and the psychological violence he has to deal with on a daily basis.
In New York, Dally blew off steam in gang fights, but here, organized gangs are rarities – […] and the warfare is between the social classes. (1.47)
Pony is trying to put things into perspective for us and let us know that the violence isn't between groups of Greasers.
"A fair fight isn't rough […]. Blades are rough. So are chains and heaters and pool sticks and rumbles. Skin fighting isn't rough. It blows off steam better than anything. (2.91)
Basically, Pony seems to be arguing that fair fighting isn't violence but sport, an activity that's beneficial to energetic boys. What do you think? How is "rumbling" similar to or different from sports like football or hockey?
Johnny was breathing heavily and I noticed he was staring at the Soc's hand. He was wearing three heavy rings." (3.49)
That Soc is Bob. When Johnny sees his rings, he knows Bob is the guy who used his face as a punching bag. Seeing Johnny watch the rings is how Pony begins to also figure out that Bob was Johnny's attacker.
Suddenly it was deathly quiet. We had all frozen. Nobody in my family had ever hit me. Nobody. (3.103)
This is a really pivotal moment in the story. It's not that Ponyboy has never been hit before, it's just that he's used to violence occurring out on the streets, not at home. Darry's violence toward Pony pushes Pony out into the night, and is what makes him decide to go to the park at two in the morning.
"Johnny! I nearly screamed. "What are we gonna do? They put you in the electric chair for killing people!" (4.32)
Pony's starting to see a long chain of violent acts stretching out before him. This fear of more violence is a big part of why he and Johnny run.
It was too vast a problem to be just a personal thing. There should be some help, someone should tell them before it was too late. (12.65)
When Pony becomes inspired to write about his experiences, his thoughts clarify and he realizes that with pen and paper he might find a nonviolent approach to trying to change the situation.
"You're the guy that killed Bob Sheldon. […] And he was a friend of ours. We don't like nobody killing our friends, especially greasers." (12.4)
Pony responds to this threat by breaking a bottle and then threatening the Socs with it. At this point in the story, he's in bad shape and hasn't been able to process any of the recent events. He seems to be changing, looking more to violence as a way to ward off the violence of the Socs.