From "Manual of Muad'Dib" by the Princess Irulan

That must not happen , he told himself.
"Is that the name you wish, Muad'Dib?" Stilgar asked.
"I am an Atreides," Paul whispered, and then louder: "It's not right that I give up entirely the name my father gave me. Could I be known among you as Paul-Muad'Dib?"
"You are Paul-Muad'Dib," Stilgar said.
And Paul thought: That was in no vision of mine. I did a different thing .
But he felt that the abyss remained all around him.
Again a murmuring response went through the troop as man turned to man: "Wisdom with strength . . . Couldn't ask more . . . It's the legend for sure . . . Lisan al-Gaib . . . Lisan al-Gaib . . . "
"I will tell you a thing about your new name," Stilgar said. "The choice pleases us. Muad'Dib is wise in the ways of the desert. Muad'Dib creates his own water. Muad'Dib hides from the sun and travels in the cool night. Muad'Dib is fruitful and multiplies over the land. Muad'Dib we call 'instructor-of-boys.' That is a powerful base on which to build your life, Paul-Muad'Dib, who is Usul among us. We welcome you."
Stilgar touched Paul's forehead with one palm, withdrew his hand, embraced Paul and murmured, "Usul."
As Stilgar released him, another member of the troop embraced Paul, repeating his new troop name. And Paul was passed from embrace to embrace through the troop, hearing the voices, the shadings of tone; "Usul . . . Usul . . . Usul." Already, he could place some of them by name. And there was Chani who pressed her cheek against his as she held him and said his name.
Presently Paul stood again before Stilgar, who said: "Now, you are of the Ichwan Bedwine, our brother." His face hardened, and he spoke with command in his voice. "And now, Paul-Muad'Dib, tighten up that stillsuit." He glanced at Chani. "Chani! Paul-Muad'Dib's nose plugs are as poor a fit I've ever seen! I thought I ordered you to see after him! "
"I hadn't the makings, Stil," she said. "There's Jamis' of course, but—"
"Enough of that!"
"Then I'll share one of mine," she said. "I can make do with one until—"
"You will not," Stilgar said. "I know there are spares among us. Where are the spares? Are we a troop together or a band of savages?"
Hands reached out from the troop offering hard, fibrous objects. Stilgar selected four, handed them to Chani. "Fit these to Usul and the Sayyadina."
A voice lifted from the back of the troop: "What of the water, Stil? What of the literjons in their pack?"
"I know your need, Farok," Stilgar said. He glanced at Jessica. She nodded.
"Broach one for those that need it," Stilgar said. "Watermaster . . . where is a watermaster? Ah, Shimoom, care for the measuring of what is needed. The necessity and no more. This water is the dower property of the Sayyadina and will be repaid in the sietch at field rates less pack fees."
"What is the repayment at field rates?" Jessica asked.
"Ten for one," Stilgar said.
"But—"
"It's a wise rule as you'll come to see," Stilgar said.
A rustling of robes marked movement at the back of the troop as men turned to get the water.
Stilgar held up a hand, and there was silence. "As to Jamis," he said, "I order the full ceremony. Jamis was our companion and brother of the Ichwan Bedwine. There shall be no turning away without the respect due one who proved our fortune by his tahaddi-challenge. I invoke the rite . . . at sunset when the dark shall cover him."
Paul, hearing these words, realized that he had plunged once more into the abyss . . . blind time. There was no past occupying the future in his mind . . . except . . . except . . . he could still sense the green and black Atreides banner waving . . . somewhere ahead . . . still see the jihad's bloody swords and fanatic legions.
It will not be , he told himself. I cannot let it be .
God created Arrakis to train the faithful.
—from "The Wisdom of Muad'Dib" by the Princess Irulan
In the stillness of the cavern, Jessica heard the scrape of sand on rock as people moved, the distant bird calls that Stilgar had said were the signals of his watchmen.
The great plastic hood-seals had been removed from the cave's opening. She could see the march of evening shadows across the lip of rock in front of her and the open basin beyond. She sensed the daylight leaving them, sensed it in the dry heat as well as the shadows. She knew her trained awareness soon would give her what these Fremen obviously had—the ability to sense even the slightest change in the air's moisture.
How they had scurried to tighten their stillsuits when the cave was opened!
Deep within the cave, someone began chanting:
"Ima trava okolo!
I korenja okolo!"
Jessica translated silently: These are ashes! And these are roots! "
The funeral ceremony for Jamis was beginning.
She looked out at the Arrakeen sunset, at the banked decks of color in the sky. Night was beginning to utter its shadows along the distant rocks and the dunes.
Yet the heat persisted.
Heat forced her thoughts onto water and the observed fact that this whole people could be trained to be thirsty only at given times.
Thirst.
She could remember moonlit waves on Caladan throwing white robes over rocks . . . and the wind heavy with dampness. Now the breeze that fingered her robes seared the patches of exposed skin at cheeks and forehead. The new nose plugs irritated her, and she found herself overly conscious of the tube that trailed down across her face into the suit, recovering her breath's moisture.
The suit itself was a sweatbox.
"Your suit will be more comfortable when you've adjusted to a lower water content in your body , " Stilgar had said.
She knew he was right, but the knowledge made this moment no more comfortable. The unconscious preoccupation with water here weighed on her mind. No , she corrected herself: it was preoccupation with moisture.
And that was a more subtle and profound matter.
She heard approaching footsteps, turned to see Paul come out of the cave's depths trailed by the elfin-faced Chani.