Preface, Sanctus, and Benedictus
The transition to the heavenly altar is evident through the words of the preface and reinforces the words that were recited or chanted in the Sursum Corda. The proper preface begins with the priest, on behalf of the people, reflecting upon how and why it is meet and right to give thanks unto our Lord God (as was stated in the Sursum Corda). Why is it meet and right to give thanks unto God for allowing us entrance into the heavenly temple? What aspect of the ministry of Christ are we focused upon? In ordinary time, we simply declare that it is "meet, right, and our bounden duty," but during specific seasons and feast days there is a proper preface that is added to reinforce what aspect of the work of Christ we are particularly mindful of at that time.
For example, the preface for Easter reflects upon our praise for the “glorious resurrection of thy Son Jesus Christ.” In Pentecost we consider we were, ”brought out of darkness and error into the clear light and true knowledge of thee,” at the Ascension it is Christ who "ascended up into heaven, to prepare a place for us,” and on Trinity Sunday it is the nature of the Triune God who is "One Lord, in Trinity of Persons and in Unity of Substance.”
We are in the presence of the Angels, Archangels, and all the company of heaven, and so we join the heavenly chorus with the singing of Holy, Holy, Holy (as referenced in Isa. 6:3 and Rev. 4:8). We are surrounded by the great cloud of witnesses to observe the sacrifice of Christ, who was slain before the foundation of the world (Rev. 13:8). Christ is not sacrificed again and again, having to offer and re-offer His blood on the altar. Rather, Christ was sacrificed once and for all time, with that sacrifice being both before the foundation of the world while also at a fixed point in time at a fixed location on the cross.
This is part of the holy mystery. How was Jesus slain before the foundation of the world but also laid on the cross at a specific point in time? How can we partake of the real presence, the body and blood of Jesus, if His body was glorified and He sits enthroned in heaven? God does not operate solely in time, and when we enter into this holy mystery, we are brought outside of time itself to participate in this Holy Mystery whereby we behold that lamb of God, sacrificed for us, who takes away the sins of the world.
This is why church architecture often has angelic, paradise, and saint imagery. We are in the presence of the angelic choir, we are in the heavenly paradise of which Eden was a shadow, and we are with the saints who have gone before. We are gathered around the heavenly altar to witness the mystery of the atonement. We couldn't be there with the Blessed Virgin and St. John at the foot of the cross, but we can be present at the foot of the heavenly altar to be in the presence of Christ, whose blood was shed once and for all time, for all humanity.
(as published in St Luke's Sunday Bulletin, 7/22/18)