Ponyboy tells the reader that the differences between his group of greaser friends and most gangs are that they treat each other like family: like brothers. Always sticking together is one rule; another rule the Curtis brothers follow is to always leave their front door open so other buddies can have a place to rest or crash for the night. Pony tells Cherry that
You take up for your buddies no matter what they do.... If you don't stick up for them, stick together, make like brothers, it isn't a gang anymore. It's a pack. A snarling, distrustful pack like the Socs... or the street gangs in New York.
However, as Two-Bit points out, sometimes they have to "pay up" when they get caught by a rival gang member, as Dally does after slashing Tim Shepard's tires. Nevertheless, Pony's gang is loyal, no matter what. Two-Bit assures Cherry that
"If we needed them tomorrow, they'd show... If (Dally) asks us for help in a rumble, we'll show."
In chapter two of The Outsiders, Pony, Johnny and Dally have gone to the drive-in. They meet Cherry and Marcia, and Pony and Johnny are smitten by the two girls. Dally, on the other hand, runs his mouth and shows how tough he is. Cherry is not impressed and says so. Dally keeps bothering the two girls, and Johnny speaks up and tells Dally to stop. Everyone is shocked that Johnny would stand up to Dally; he idolized Dally. After Dally leaves, Cherry invites Pony and Johnny to sit with them and makes a remark about how bad Dally is, but Johnny defends him:
"Dally's okay," Johnny said defensively and I nodded. You take up for your buddies, no matter what they do. When you're a gang, you stick up for the members. If you don't stick up for them, stick together, make like brothers, it isn't a gang anymore. It's a pack. A snarling, distrustful, bickering pack like the Socs in their social clubs or the street gangs in New York or the wolves in the timber. "He's tough, but he's a cool old guy."
Pony is trying to explain that in a gang you always stick together and have each other's backs no matter what. Little did Pony know that this was the night that would change everything in Pony's and Johnny's lives. The rule the Greasers had would be put to the ultimate test.
The Greaser rules are stick together and don't get caught.