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

The shock must be severe and he's almost ready for it , she thought.
"You listen respectfully to me in Council," she said, "yet you seldom heed my advice. Why?"
"I don't trust your Bene Gesserit motives," he said. "You may think you can look through a man; you may think you can make a man do exactly what you—"
"You poor fool , Thufir!" she raged.
He scowled, pushing himself back in the chair.
"Whatever rumors you've heard about our schools," she said, "the truth is far greater. If I wished to destroy the Duke . . . or you, or any other person within my reach, you could not stop me."
And she thought: Why do I let pride drive such words out of me? This is not the way I was trained. This is not how I must shock him .
Hawat slipped a hand beneath his tunic where he kept a tiny projector of poison darts. She wears no shield , he thought. Is this just a brag she makes? I could slay her now . . . but, ah-h-h-h, the consequences if I'm wrong .
Jessica saw the gesture toward his pocket, said: "Let us pray violence shall never be necessary between us."
"A worthy prayer," he agreed.
"Meanwhile, the sickness spreads among us," she said. "I must ask you again: Isn't it more reasonable to suppose the Harkonnens have planted this suspicion to pit the two of us against each other?"
"We appear to've returned to stalemate," he said.
She sighed, thinking: He's almost ready for it .
"The Duke and I are father and mother surrogates to our people," she said. "The position—"
"He hasn't married you," Hawat said.
She forced herself to calmness, thinking: A good riposte, that .
"But he'll not marry anyone else," she said. "Not as long as I live. And we are surrogates, as I've said. To break up this natural order in our affairs, to disturb, disrupt, and confuse us—which target offers itself most enticingly to the Harkonnens?"
He sensed the direction she was taking, and his brows drew down in a lowering scowl.
"The Duke?" she asked. "Attractive target, yes, but no one with the possible exception of Paul is better guarded. Me? I tempt them, surely, but they must know the Bene Gesserit make difficult targets. And there's a better target, one whose duties create, necessarily, a monstrous blind spot. One to whom suspicion is as natural as breathing. One who builds his entire life on innuendo and mystery." She darted her right hand toward him. "You!"
Hawat started to leap from his chair.
"I have not dismissed you, Thufir!" she flared.
The old Mentat almost fell back into the chair, so quickly did his muscles betray him.
She smiled without mirth.
"Now you know something of the real training they give us," she said.
Hawat tried to swallow in a dry throat. Her command had been regal, preemptory—uttered in a tone and manner he had found completely irresistible. His body had obeyed her before he could think about it. Nothing could have prevented his response—not logic, not passionate anger . . . nothing. To do what she had done spoke of a sensitive, intimate knowledge of the person thus commanded, a depth of control he had not dreamed possible.
"I have said to you before that we should understand each other," she said. "I meant you should understand me . I already understand you. And I tell you now that your loyalty to the Duke is all that guarantees your safety with me."
He stared at her, wet his lips with his tongue.
"If I desired a puppet, the Duke would marry me," she said. "He might even think he did it of his own free will."
Hawat lowered his head, looked upward through his sparse lashes. Only the most rigid control kept him from calling the guard. Control . . . and the suspicion now that woman might not permit it. His skin crawled with the memory of how she had controlled him. In the moment of hesitation, she could have drawn a weapon and killed him!
Does every human have this blind spot? he wondered. Can any of us be ordered into action before he can resist? The idea staggered him. Who could stop a person with such power?
"You've glimpsed the fist within the Bene Gesserit glove," she said. "Few glimpse it and live. And what I did was a relatively simple thing for us. You've not seen my entire arsenal. Think on that,"
"Why aren't you out destroying the Duke's enemies?" he asked.
"What would you have me destroy?" she asked. "Would you have me make a weakling of our Duke, have him forever leaning on me?"
"But, with such power . . . "
"Power's a two-edged sword, Thufir," she said; "You think: 'How easy for her to shape a human tool to thrust into an enemy's vitals.' True, Thufir; even into your vitals. Yet, what would I accomplish? If enough of us Bene Gesserit did this, wouldn't it make all Bene Gesserit suspect? We don't want that, Thufir. We do not wish to destroy ourselves." She nodded. "We truly exist only to serve."
"I cannot answer you," he said. "You know I cannot answer."
"You'll say nothing about what has happened here to anyone," she said. "I know you, Thufir."
"My Lady . . . " Again the old man tried to swallow in a dry throat.
And he thought: She has great powers, yes. But would these not make her an even more formidable tool for the Harkonnens?
"The Duke could be destroyed as quickly by his friends as by his enemies," she said. "I trust now you'll get to the bottom of this suspicion and remove it."
"If it proves baseless," he said.
"If, " she sneered.
"If," he said.
"You are tenacious," she said.
"Cautious," he said, "and aware of the error factor."
"Then I'll pose another question for you: What does it mean to you that you stand before another human, that you are bound and helpless and the other human holds a knife at your throat—yet this other human refrains from killing you, frees you from your bonds and gives you the knife to use as you will?"
She lifted herself out of the chair, turned her back on him. "You may go now, Thufir."
The old Mentat arose, hesitated, hand creeping toward the deadly weapon beneath his tunic. He was reminded of the bull ring and of the Duke's father (who'd been brave, no matter what his other failings) and one day of the corrida long ago: The fierce black beast had stood there, head bowed, immobilized and confused. The Old Duke had turned his back on the horns, cape thrown flamboyantly over one arm, while cheers rained down from the stands.
I am the bull and she the matador , Hawat thought. He withdrew his hand from the weapon, glanced at the sweat glistening in his empty palm.
And he knew that whatever the facts proved to be in the end, he would never forget this moment nor lose this sense of supreme admiration for the Lady Jessica.
Quietly, he turned and left the room.
Jessica lowered her gaze from the reflection in the windows, turned, and stared at the closed door.
"Now we'll see some proper action," she whispered.
Do you wrestle with dreams?
Do you contend with shadows?
Do you move in a kind of sleep?
Time has slipped away.
Your life is stolen.
You tarried with trifles,
Victim of your folly.
—Dirge for Jamis on the Funeral Plain,