A Requiem (Latin: rest) or Requiem Mass, also known as Mass for the dead (Latin: Missa pro defunctis) or Mass of the dead (Latin: Missa defunctorum), is a Mass of the Catholic Church offered for the repose of the souls of the deceased…
The first verse is a call to God in deep sorrow, from "out of the depths" or "out of the deep", as it is translated in the King James Version of the Bible and the Coverdale translation (used in the Book of Common Prayer), respectively.