In the letter that Johnny writes to Ponyboy and leaves him to read after his death, he actually gives quite a good analysis of the message of the Frost poem, "Nothing Gold Can Stay." Of course, Johnny's own personal situation cannily mirrors the theme of the poem as well, as Johnny recognises that he is dying and shows in his letter a brave acceptance of the fact. Note what he says:
Listen, I don't mind dying now. It's worth it... I've been thinking about it, and that poem, that guy that wrote it, he meant you're gold when you're a kid, like green. When you're a kid everything's new, dawn. It's just when you get used to everything that it's day.
Johnny thus intimately connects the content and message of the poem to his life and the lives of his gang. Of course, another motif in the novel is that of sunsets, and Johnny sees Ponyboy's ability to look at and enjoy sunsets as evidence of his childhood and how everything is still "gold" for Ponyboy. The Frost poem talks about innocence and experience, and how in our youth we are "golden" through our innocence, but how as we grow up, we become experienced and world-weary, "So Eden sank to grief." The sombre message of the poem, "Nothing gold can stay," is of course shown through the lives of the gang, who struggle against so many issues and have had to grow up incredibly quickly. Johnny, however, recognises that any evidence of our innocence is precious and must be clung on to as something valuable, which is why he asks Ponyboy to tell Dally to start looking at sunsets.