The Catechism in Questions & Answers

629. How are listeners prepared for the forgiveness of sins and the celebration of Holy Communion?

Listeners are prepared for the forgiveness of sins and the celebration of Holy Communion by appropriate words from the officiant. Together, they sing a hymn of repentance in preparation for the forgiveness of sins. In it, the members of the congregation profess their sinfulness and bring to expression their need for help.