Towards the end of chapter 9, Johnny's final words to Ponyboy before he dies are to "Stay gold," which is his way of telling Ponyboy to remain innocent and recognize the positive aspects of life. When Ponyboy and Johnny were hiding out in Windrixville, both boys witnessed a serene sunrise, which reminded Ponyboy of the well-known Robert Frost poem "Nothing Gold Can Stay." In the short poem, Frost explores the transience of youth, beauty, and life using the metaphor of spring's ending. Initially, Ponyboy does not comprehend the true meaning of the poem but recites the poem to Johnny. As the story progresses, Johnny suffers a serious back injury during the church fire and is taken to the hospital's critical care unit.
Following the rumble, Ponyboy and Dally visit Johnny on his death bed, where he references the Robert Frost poem by telling Ponyboy to "Stay gold." After Johnny dies, Ponyboy finds a letter that Johnny had written to him before he passed away. In the letter, Johnny explains the meaning of the poem to Ponyboy by writing,
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. Like the way you dig sunsets, Pony. That's gold. Keep that way, it's a good way to be.
Johnny recognizes the meaning of the poem and wants Ponyboy to retain his childlike innocence and purity. Johnny does not want Ponyboy to develop into a hardened, tough individual like Dally and wants him to remain a compassionate, sensitive person who appreciates the natural environment and is sympathetic towards others.