The purpose of the prelude is to set the stage and to assist the congregation in preparing their hearts and minds for the service. Preludes are often based on hymns, which call to mind a particular text and offer further opportunity for meditation on God’s Word, and they reflect the character and mood of the day or season.
Most services formally begin with the Invocation: “In the name of the Father and of the + Son and of the Holy Spirit.” In the beginning, all three persons of the Trinity were present and active in creating the world (Genesis 1:1-3). So also all three persons of the Trinity are active in creating new life in the waters of Holy Baptism as God speaks the words of Christ through the pastor, “I baptize you in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). In Baptism, the name of God is given to us, and we are brought into His family.
Scripture also tells us that where God’s name is, there He is present: “In every place where I record My name I will come to you, and I will bless you,” (Exodus 20:24) and, “For where two or three are gathered in my name, there am I among them” (Matthew 18:20). God’s name does not indicate an abstract presence, but that He is present and actively working to bless His people in that place. God is present everywhere, but in the Divine Service He is present in a sacramental way to bless us with His gifts.
Beginning the Divine Service with the Invocation reminds us that we are gathered together as baptized Christians and members of one family as brothers and sisters in Christ. It is also a proclamation that God is present and active in our midst working through the liturgy to deliver to us the forgiveness of sins, life, and salvation. It is not we who call God down to earth, but God who gathers us together to continue the work He began in our Baptism as He serves us in the Divine Service.
The Lutheran Service Book includes the rubric, “The sign of the cross + may be made by all in remembrance of their Baptism” (p. 151). The sign of the cross was first traced on us in our Baptism: “Receive the sign of the holy cross both upon your + forehead and upon your + heart to mark you as one redeemed by Christ the crucified” (p. 268). Making the sign of the cross at the Invocation and at other times during the liturgy is an ancient practice that reminds us that we enter into God’s presence having been clothed with Christ’s righteousness in our Baptism to receive His holy gifts as fellow heirs with Christ.