You put the killing thing right between your teeth, but you don't give it the power to do its killing

The expression "You put the killing thing right between your teeth, but you don't give it the power to do its killing" is a defining metaphor in John Green's The Fault in Our Stars, first spoken by Augustus Waters to Hazel Grace Lancaster outside the church after their initial Support Group meeting. It crystallizes Augustus's personal philosophy of holding danger at bay through symbolic mastery, and it reverberates through the novel as a touchstone for his character, his relationship with Hazel, and the story's broader exploration of how to live with the certainty of death.

Origin and First Use

Augustus first deploys the line in Chapter One, immediately after Hazel has angrily confronted him about the pack of cigarettes he pulls out in the church parking lot. She accuses him of being a hypocrite—a cancer survivor who "gives money to a company in exchange for the chance to acquire YET MORE CANCER." In response, Augustus explains that the cigarettes are never lit. "They don't kill you unless you light them," he says, "and I've never lit one. It's a metaphor, see: You put the killing thing right between your teeth, but you don't give it the power to do its killing." The explanation reframes what Hazel initially reads as reckless or performative as a deliberate, almost philosophical act: a daily rehearsal of control over the very thing that could destroy him. Augustus later confirms his commitment to this principle, telling Hazel, "I'm a big believer in metaphor, Hazel Grace." The unlit cigarette becomes his signature prop, appearing in scenes ranging from the intimate—sitting with Hazel on a park bench in Amsterdam—to the absurd, as when a flight attendant informs him that "that metaphor is prohibited on today's flight."

The Metaphor's Function in Augustus's Character

The unlit cigarette serves as a tangible emblem of Augustus's deepest fears and his strategy for managing them. He confesses at Support Group that he "fear[s] oblivion," and the cigarette ritual allows him to stare down that fear without being consumed by it. The metaphor also aligns with his broader obsession with leaving a meaningful mark—a legacy that transcends his own mortality. He tells Hazel that "all salvation is temporary" but that buying someone "a minute" might buy them "an hour, which is the hour that buys them a year." The cigarette, perpetually unlit, is his way of buying himself that minute, of asserting agency in a world he knows is not a wish-granting factory. Yet the metaphor also reveals a tension: Augustus wants to be the kind of person who can hold the killing thing without being killed, but his body ultimately betrays him. When his cancer recurs and he deteriorates, the cigarette remains unlit, but the power it was meant to contain—the power of disease and death—overwhelms him anyway. In his final, desperate act, he sneaks out of the house to buy a new pack, only to end up vomiting in his car with a malfunctioning G-tube, stripped of the dignity the metaphor was supposed to preserve.

The Metaphor in Hazel's Understanding

Hazel initially dismisses the cigarette as a pose, but she comes to understand its deeper resonance. After Augustus reveals his cancer recurrence in Amsterdam, she sees the unlit cigarette not as a gimmick but as a fragile shield. The metaphor also echoes her own self-conception as a "grenade"—someone who will inevitably hurt those she loves. Where Augustus tries to control the killing thing by keeping it unlit, Hazel tries to control the damage by keeping people at a distance. Both strategies fail, but the novel suggests that the attempt itself has value. In her eulogy at Augustus's prefuneral, Hazel speaks of "infinite numbers" and "some infinities [being] bigger than other infinities," a mathematical metaphor that, like Augustus's cigarette, tries to give shape and meaning to what is formless and overwhelming. The two metaphors—the unlit cigarette and the grenade—mirror each other: one is about holding danger close without letting it act; the other is about pushing people away to protect them from the explosion. Together, they define the central romantic and philosophical tension of the novel.

The Metaphor's Thematic Significance

The unlit cigarette metaphor is part of a larger pattern in The Fault in Our Stars of characters using symbols, rituals, and language to impose order on chaos. Augustus's "Encouragements" at home, his memorized soliloquy at the Dutch-themed picnic, and his insistence on a prefuneral all reflect the same impulse: to frame experience in a way that makes it bearable. The cigarette is the most personal and persistent of these frames. It also connects to the novel's engagement with Peter Van Houten's An Imperial Affliction, a book that refuses to provide closure or meaning. Augustus's metaphor is, in a sense, his answer to Van Houten's nihilism: even if the universe is indifferent, even if oblivion is certain, one can still choose how to hold the killing thing. The metaphor does not defeat death, but it transforms the relationship to it. When Hazel slips a pack of Camel Lights into Augustus's coffin at his funeral, whispering, "You can light these. I won't mind," she honors the metaphor even in its final, ironic inversion: the killing thing is now beside him, and he no longer needs to keep it unlit.