Gandalf says “You shall not pass!” while confronting the Balrog in J.R.R. Tolkien’s The Lord of the Rings.
The scene occurs on the Bridge of Khazad-dûm in Moria. After the Fellowship escapes the Orcs and the Balrog, Gandalf stands on the narrow bridge to prevent the creature from pursuing the others. He breaks the bridge beneath the Balrog, but the monster’s whip catches him and pulls him into the abyss.
Gandalf later returns as Gandalf the White after defeating the Balrog, which Tolkien identifies as a being of the same broad order of spiritual creature as Gandalf himself. His return changes his role and appearance, and he becomes the leader of the resistance against Sauron.
The exact wording is associated especially with the film adaptation, while Tolkien’s book version has closely related dialogue: “You cannot pass.” Both versions describe the same confrontation. Gandalf’s stand allows the surviving members of the Fellowship to escape Moria.