To study music theory is to devote oneself to the analysis of musical forms. Theorists spend hours studying the details of any given musical form, which convey to us that there is a deeper emotional and musical communication that can be intended by a composition. Form is an important part of communicating musically. The same is true for the form of the liturgy of the western church.
Recently it dawned on me that the words of the Agnus Dei, "O Christ, Thou Lamb of God, that takest away the sin of the world, have mercy upon us," which are at the end of the service, are also found in the Gloria in Excelsis in the beginning of the service. However, In the Gloria this phrase is slightly modified, "O Lord God, Lamb of God, Son of the Father, that takest away the sin of the world, have mercy upon us." The beauty of this discovery is that this is a fundamental prayer of the Christian Church. This prayer admits that we are destined for death, that we need God’s mercy, and that there is nothing we can do to change our predicament. In this confession we find our hope. Jesus, who was like a lamb, was led to the slaughter for our sins. Jesus willingly took our sins upon himself. Jesus has thus had great mercy on us. That is the church’s confession - it is a statement of faith about the person who gives us hope. The way this wonderful prayer is used in the liturgy adds depth to one’s understanding of Jesus Christ’s redemptive work.
This phrase, used in both the Gloria and the Agnus Dei, also acts as a signal that forgiveness of sins, life, and salvation are near. After the Gloria is sung in the Divine Service, we proceed with the Salutation and Collect for the Day. Then our Lord is with us through His Words. Later in the service we sing the Agnus Dei. Then our Lord is physically with us in the Eucharist. After praying these words we receive our Lord for the purification of our corruption. This phrase alerts us that our Lord Jesus is present with us in the ways that have been promised: through His Words and in the Sacraments. What is happening at these points in the Liturgy is nothing less than the Lord’s compassionate response to our cry for mercy.
This phrase also confesses the purpose of the life of Jesus. The Gloria starts with the words of the nativity, "Glory be to God on high and on earth peace, goodwill toward men." When we pray for “the Lamb of God" to have mercy on us we link the birth of the Jesus to the purpose of his death - the salvation of the world. When we pray these words in the Agnus Dei we acknowledge that Jesus’ death has made atonement for the fallen world. We also confess that Jesus is with us both spiritually and physically in this age. The man who was born of a virgin outside of Bethlehem is the same man who justified sinners through his death. This is the same man who is now with us in His Word and in His Sacraments.
"O Christ, thou lamb of God, that takest away the sin of the world, have mercy upon us!"
*My spiritual father, Pr. Esget, provided me with insight into the depth of the use of this phrase in the liturgy. The whole article has been influenced by him.
*Many thanks are due to my beloved Kyle.
*All quotations of the Liturgy are from The Lutheran Hymnal.
The Lutheran Hymnal. St. Louis: Concordia Publishing House, 1941.