The Congregation for Divine Worship and the Sacraments has dropped the hammer on one of the more prevalent — and ridiculous-sounding — liturgical innovations: troping during the Agnus Dei, which usually involves a cantor “free-styling” the words like a poetry slammer or, more often, using the setting from Haugen’s Mass of Creation, e.g., substituting “Prince of Peace” for “Lamb of God.”
In response to a request from the Congregation for Divine Worship and the Discipline of the Sacraments, the USCCB Administrative Committee adopted a change on September 12, 2012 to the U.S. Bishops’ 2007 guidelines on liturgical music, Sing to the Lord: Music in Divine Worship. Number 188 of the document has been altered to remove any further permission for the use of Christological tropes or other adaptations to the text of the Agnus Dei (Lamb of God).
One of the reasons the correction was required is the confusion created by the USCCB’s 2007 document “Sing to the Lord,” which claimed one can use tropes when the Agnus Dei is sung as a hymn and not during its respective place in the ordinary of the Mass. Some liturgists forgot the context and interpreted it loosely. Regardless, the document was never submitted to the Holy See for recognitio and so lacks any authority.