The quote 'The power of Christ compels you!' is the climax of 'The Exorcist.' The film's musical legend, however, is 'Tubular Bells' by Mike Oldfield. Tubular bells are orchestral instruments made of long metal tubes struck with mallets to mimic church bells. Oldfield’s repetitive, minimalist use of the bells (along with piano and organ) created a cold, detached atmosphere that became the sound of demonic possession. Director William Friedkin chose the track because its 'mechanical' precision felt unsettling. The success of the film made 'Tubular Bells' a global phenomenon and established the bells as a staple of horror cinema. It proved that an instrument typically used for celebratory church sounds could be subverted to become a symbol of terror, perfectly backing the most intense religious dialogue in movie history.