" Merrin stood up and prayed reverently: “ ‘God, Creator and defender of the human race, look down in pity on this your servant, Regan Teresa MacNeil, now trapped in the coils of man’s ancient enemy, sworn foe of our race, who…’ ” Karras glanced up as he heard Regan hissing, saw her sitting erect with the whites of her eyes exposed, while her tongue flicked in and out rapidly, her head weaving slowly back and forth like a cobra’s, and once again he had that feeling of disquiet. He looked down at his text. “ ‘Save your servant,’ ” prayed Merrin, standing and reading from the Ritual. “ ‘Who trusts in you, my God,’ ” answered Karras. “ ‘Let her find in you, Lord, a fortified tower.’ ” “ ‘In the face of the enemy.’ ” As Merrin continued with the next line—“Let the enemy have no power over her”—Karras heard a gasp from Sharon behind him, and turning quickly around, he saw her looking stupefied "

― William Peter Blatty , The Exorcist