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.

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.

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 ...