(The following is from Rev. Bart Day, Executive Director, LCMS Office of National Mission, in a 04/21/15 email to LCMS congregations.)
Sunday is not a Christian Sabbath nor is it an attempt to historicize the past. Rather, Sunday is the day symbolic of the continued presence of the risen Christ who remains active in our midst.
Sunday is the expression of all Christian liturgy – the result of which is what we become: the body of Christ, the oil of healing for the world, the sweet smelling aroma of prayers lifted before the throne of the Father.
Sunday is the first day. It is the day of primordial creation when God called all things into existence from nothing. Sunday is the beginning of all that will be in Christ. It is the day of light. Darkness and light forever separated by God. Jesus Christ is the Light of the world, the light no darkness can overcome.
Sunday is the day of resurrection, the inauguration of a new creation given through Christ’s sacrifice, accepted by the Father, for the life of the world. Sunday is more than a little Easter; it is the symbol of the new age begun and completed in the paschal mystery.
Sunday is the day of Eucharist. In the eating of His precious body and the drinking of His sacred blood, faith grasps and appropriates to itself what the eye cannot see. In the Eucharist, the church becomes the Kingdom of God manifest in the world, so that the love of Christ would abound in acts of love and charity.
Sunday is the eighth day, the day of eternity beyond the weekly cycle, symbolizing the kingdom, which has no end.
Is there anything that Sunday doesn’t mean? In the words of Robert Taft, “For the Early Church, Sunday was indeed everything. … It is the day symbolic of all days, for the purpose of all Christian liturgy is to express in a ritual moment that which should be the basic stance of every moment of our lives”
(Beyond East and West, p. 52).