I believe there are several themes covered in Chapter 6 of The Outsiders. One is that of owning up to one's mistakes. Johnny decides for himself that he (along with Pony) is going to return to Tulsa and turn himself in to the authorities. Johnny doesn't think it's fair that Pony's brothers should be worried about him and wondering if he is alive or dead. Secondly, when the boys see the church fire, they immediately realize that they caused it by leaving their cigarettes burning. They quickly decide that it's their responsibility to save the children inside.
The other primary theme is that of family togetherness. Although Johnny's family life is a bad one, he misses his greaser pals. Pony is also ready to return to ease his brothers' minds. The final scene of the chapter reunites the three Curtis brothers, and Pony realizes how deeply Darry is affected by his absence when he sees his tears. Pony realizes that he has been at fault for not recognizing this.
The most important revelation in this chapter is Ponyboy’s redefinition of his family. From talking with both Dally and Johnny, Ponyboy realizes how lucky he is to have two brothers—not just gang-member brothers, but two real brothers. Pony internally admits that he loves them both even if they aren’t always the way he wants them to be