The Voice of Saruman
The Voice of Saruman is the tenth chapter of the third book in The Two Towers.
Gandalf warns everyone about Saruman's voice, which has powers beyond their imagination. Theoden, Aragorn, Legolas and Gimli decide to go with Gandalf to get a first hand view of Saruman. When Saruman does appear, his voice sounds like the sweetest anyone has ever heard. He speaks to Theoden and tries to persuade him to be his friend. Gandalf doesn't say a word because he has to let Theoden make his own choices: either succumb to Saruman's wizardry or fight it. Gimli is not taken in and neither is Eomer. Eventually Theoden is able to control himself and he rejects Saruman's appeal.
Theoden's men have fallen under Saruman's spell and are confused by their leader's rejection. Saruman is angered and when his voice changes the men realize their mistake in falling for his tricks. Gandalf gives Saruman a chance to discard his evil ways, but Saruman not only does not take Gandalf's offer, he even tries to persuade Gandalf to join him. When Gandalf asks him once more to come out of Orthanc, Saruman turns away. Gandalf raises his hand and commands Saruman's staff to break. Saruman's staff breaks and he falls back. At that Wormtongue hurls an object at Gandalf but misses and Pippin picks it up. Gandalf retrieves it, recognizing it at once as a palantir (a seeing stone). Gandalf knows that though Saruman is a lost cause, this is a great treasure.
Gandalf asks Treebeard to pour back the water into Orthanc so that Saruman can never escape. Treebeard agrees.