The Exorcist - Season 1, Episode 1: Soundtracks

Playing outside Father Marcus' home in Mexico City, Father Bennett from the Vatican visits him concerning his actions.

Father Tomas visits Father Marcus in St. Aquinas where random patients are singing along to this song in various rooms.

Ending as Father Tomas looks up as Angela's daughter Casey, looks out at him from her bedroom.

Mrs. Finley plays “Zion hears the watchmen singing” on the organ in the church for a few notes before the organ errors out.