Episode 5 of Dune: Prophecy revealed the true reason ... and Paul both call upon to center themselves in dire times. "I must not fear," the Litany goes. "Fear is the mind-killer.

There's a mantra repeated in the world of "Dune" about the nature of fear, and the effects it can have on a person's mental state. "I must not fear. Fear is the mind-killer. Fear is the little ...

Lady Jessica quietly recites this to herself during her Litany against Fear while her son Paul faces the leader of the Bene Gesserit in Frank Herbert’s novel “Dune”: “I must not fear.