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

The size of the attack .
He had always expected their enemy to hire an occasional lighter from the Guild for probing raids. That was an ordinary enough gambit in this kind of House-to-House warfare. Lighters landed and took off on Arrakis regularly to transport the spice for House Atreides. Hawat had taken precautions against random raids by false spice lighters. For a full attack they'd expected no more than ten brigades.
But there were more than two thousand ships down on Arrakis at the last count—not just lighters, but frigates, scouts, monitors, crushers, troop-carriers, dump-boxes . . .
More than a hundred brigades—ten legions!
The entire spice income of Arrakis for fifty years might just cover the cost of such a venture.
It might .
I underestimated what the Baron was willing to spend in attacking us , Hawat thought. I failed my Duke .
Then there was the matter of the traitor.
I will live long enough to see her strangled! he thought. I should've killed that Bene Gesserit witch when I had the chance . There was no doubt in his mind who had betrayed them—the Lady Jessica. She fitted all the facts available.
"Your man Gurney Halleck and part of his force are safe with our smuggler friends," the Fremen said.
"Good."
So Gurney will get off this hell planet. We 're not all gone .
Hawat glanced back at the huddle of his men. He had started the night just past with three hundred of his finest. Of those, an even twenty remained and half of them were wounded. Some of them slept now, standing up, leaning against the rock, sprawled on the sand beneath the rock. Their last 'thopter, the one they'd been using as a ground-effect machine to carry their wounded, had given out just before dawn. They had cut it up with lasguns and hidden the pieces, then worked their way down into this hiding place at the edge of the basin.
Hawat had only a rough idea of their location—some two hundred kilometers southeast of Arrakeen. The main traveled ways between the Shield Wall sietch communities were somewhere south of them.
The Fremen across from Hawat threw back his hood and stillsuit cap to reveal sandy hair and beard. The hair was combed straight back from a high, thin forehead. He had the unreadable total blue eyes of the spice diet. Beard and mustache were stained at one side of the mouth, his hair matted there by pressure of the looping catchtube from his nose plugs.
The man removed his plugs, readjusted them. He rubbed at a scar beside his nose.
"If you cross the sink here this night," the Fremen said, "you must not use shields. There is a break in the wall . . . " He turned on his heels, pointed south. " . . . there, and it is open sand down to the erg. Shields will attract a . . . " He hesitated. ". . . worm. They don't often come in here, but a shield will bring one every time."
He said worm , Hawat thought. He was going to say something else. What? And what does he want of us?
Hawat sighed.
He could not recall ever before being this tired. It was a muscle weariness that energy pills were unable to ease.
Those damnable Sardaukar!
With a self-accusing bitterness, he faced the thought of the soldier-fanatics and the Imperial treachery they represented. His own Mentat assessment of the data told him how little chance he had ever to present evidence of this treachery before the High Council of the Landsraad where justice might be done.
"Do you wish to go to the smugglers?" the Fremen asked.
"Is it possible?"
"The way is long."
"Fremen don't like to say no ," Idaho had told him once.
Hawat said: "You haven't yet told me whether your people can help my wounded."
"They are wounded."
The same damned answer every time!
"We know they're wounded!" Hawat snapped. "That's not the—"
"Peace, friend," the Fremen cautioned. "What do your wounded say? Are there those among them who can see the water need of your tribe?"
"We haven't talked about water," Hawat said. "We—"
"I can understand your reluctance," the Fremen said. "They are your friends, your tribesmen. Do you have water?"
"Not enough."
The Fremen gestured to Hawat's tunic, the skin exposed beneath it. "You were caught in-sietch, without your suits. You must make a water decision, friend."
"Can we hire your help?"
The Fremen shrugged. "You have no water." He glanced at the group behind Hawat. "How many of your wounded would you spend?"
Hawat fell silent, staring at the man. He could see as a Mentat that their communication was out of phase. Word-sounds were not being linked up here in the normal manner.
"I am Thufir Hawat," he said. "I can speak for my Duke. I will make promissory commitment now for your help. I wish a limited form of help, preserving my force long enough only to kill a traitor who thinks herself beyond vengeance."
"You wish our siding in a vendetta?"
"The vendetta I'll handle myself. I wish to be freed of responsibility for my wounded that I may get about it."
The Fremen scowled. "How can you be responsible for your wounded? They are their own responsibility. The water's at issue, Thufir Hawat. Would you have me take that decision away from you?"
The man put a hand to a weapon concealed beneath his robe.
Hawat tensed, wondering: Is there betrayal here?
"What do you fear?" the Fremen demanded.