On occasion, I’m asked: “By whose authority can you say the Eucharistic Prayer facing the same direction as the congregation? What Pope said you could do this?”
Up until about 1965, this was a well established practice of the Church. If you were to ask a priest before the this time, why he said Mass facing the altar, he would have looked at you as if you had two heads. Offering the Eucharistic Prayer versus populum (facing the people) is more of an aberration to the sacred rite. It was something never envisioned by the Fathers of the Second Vatican Council, but one imposed by faulty historical analysis by Liturgists who desired to make our Mass more appealing to Protestants.
So, back to some authoritative source as for the practice of ad orientem worship. The custom in itself is authoritative. Mass was celebrated facing the east (ad orientem) for over 1,900 years. The eastern rites of the Catholic Church, along with our brethren in the Orthodox Church have never deviated from this ancient and venerable tradition.
Aside from this long standing practice, the very ritual of the Roman Rite, known as the Roman Missal assumes that priests are offering the Holy Sacrifice of the Mass ad orientem.
Rubrics are directions in Liturgical books on how the service ought to be conducted. The word rubric comes from the Latin word rubrica meaning red. There are two color types in the Roman Missal, red and black. Red informs the priest what he must do and black, what he must say.
Let me quote directly from the rubrics in the Roman Missal.
“The Priest and the faithful, standing, sign themselves with the Sign of the Cross, while the Priest, facing the people, says: In the name of the Father…” (Roman Missal #1.)
“The Priest, standing at the altar, takes the paten with the bread and holds it slightly raised above the altar with both hands, saying in a low voice.” (RM #23)
“Standing at the middle of the altar, facing the people … he says: Prayer, brethren , that my sacrifice and yours may be acceptable to God the almighty Father.” (RM #29)
“The Priest, turned towards the people, extending and then joining his hands, adds: The peace of the Lord be with you always.” (RM #127)
“The Priest genuflects, takes the host and, holding it slightly raised above the paten or above the chalice, while facing the people, says aloud: Behold the Lamb of God…” (RM #132)
“The Priest, facing the altar, says quietly: May the Body of Christ keep me safe for eternal life. And he reverently consumes the Body of Christ.” (RM #133)
“Then, standing at the altar or at the chair and facing the people, with hands joined, the Priest says: Let us pray.” (RM #139)
After the collect:
“The Priest, facing the people and extending his hands, says: The Lord be with you. … May almighty God bless you…” (RM #141)
A close reading of the rubrics of the Roman Missal clearly assumes the priest is facing the altar, except for the Liturgy of the Word, and those times where it reads “facing the people,” or “turned towards the people.”
A priest must be sensitive to the people he serves. However, this does not mean avoiding, or rejecting our sacred tradition. Our sensitivity must come through proper teaching. We must help our people to have a good understanding of what ad orientem worship is, it’s theological dimensions and the great benefit it can bring to our spiritual life. At the same time, following the directives of the Roman Missal is the only authority a priest needs to celebrate Mass ad orientem. The rubrics and long standing tradition are the authoritative voice of the Church.