Johnny and Pony aren't that close in the beginning, but all that time at the church running from hardship really helps them bond. When Johnny dies Pony starts acting weird as if he died, instead of Johnny. Pony has a hard time accepting the truth that Johnny threw at him, Right before Johnny dies he says this to him "Stay gold...", at first Pony is confused but when he sees the letter that fell out of the book he realizes it means he should stay young and innocent.
Pony was born a greaser which means he isn't accepted into society and is supposed to be a rebel. Even though he likes his looks he knows it shouldn't be so stereotyped. Pony lives his life trying to change and just be a good person. Greasers and Socs don't get along so it leads Socs to beat them up whenever they feel like it. This changes Pony because it causes him to live not only a life of fear and pain but wanting to change this life set out for the rest of society.
The church is a place where Johnny and Pony bond. When the learn more about each other they become better people and are able to see more into other peoples lives. When the fire happens at the church Johnny and Pony automatically decide that it is their fault and they are the two people destined to save the kids, They run in putting their lives in danger for a couple strangers. This shows how they are heroic and proves to society that they arent just a couple of hoods.