When Ponyboy gets jumped in the street the gang is there to help him stay safe and not get hurt, because they have seen what happened to Johnny after he got really hurt. This shows honor because the gang cares for its members like a family. "If it hadn't been for the gang, Johnny wouldn't have known what love and affection are." page 12.
At the rumble both gangs understand that no weapons are going to be used. They all stay true to this agreement. This shows honor because both the gangs don't want anyone to get seriously hurt.
When the gang visits Johnny and Dally in the hospital because they care about him and his health, that shows honor for Johnny and Dally because the gang knows Johnny and Dally need to see their friends.
They let anyone in no matter what because the door is always unlocked. Steve or anybody can come in if they need to at any time. This shows honor because they understand that people might need somewhere to go.
When the Church was on fire Ponyboy and Johnny risked their lives to save the kids. This shows honor not only for the gang but for others who they don't know but care about.
When the greasers and socs were in the court room they showed honor by telling the truth and not making things up or making things worse for Ponyboy.