8. Beginning with the Upper Room and Holy Thursday, the celebration of the Eucharist has a long history, a history as long as that of the Church. In the course of this history the secondary elements have undergone certain changes, but there has been no change in the essence of the "Mysterium" instituted by the Redeemer of the world at the Last Supper. The Second Vatican Council too brought alterations, as a result of which the present liturgy of the Mass is different in some ways from the one known before the Council. We do not intend to speak of these differences: It is better that we should now concentrate on what is essential andimmutable in the Eucharistic Liturgy.
There is a close link between this element of the Eucharist and its sacredness, that is to say, its being a holy and sacred action. Holy and sacred, because in it are the continual presence and action of Christ, "the Holy One" of God,(36) "anointed with the Holy Spirit,"(37) "consecrated by the Father"(38) to lay down His life of His own accord and to take it up again,(39) and the High Priest of the New Covenant.(40) For it is He who, represented by the celebrant, makes His entrance into the sanctuary and proclaims His Gospel. It is He who is "the offerer and the offered, the consecrator and the consecrated."(41) The Eucharist is a holy and sacred action, because it constitutes the sacred species, the Sancta sanctis, that is to say, the "holy things (Christ, the Holy One) given to the Holy," as all the Eastern liturgies sing at the moment when the eucharistic Bread is raised in order to invite the faithful to the Lord's Supper.
The sacredness of the Mass, therefore, is not a "sacralization," that is to say, something that man adds to Christ's action in the Upper Room, for the Holy Thursday supper was a sacred rite, a primary and constitutive liturgy, through which Christ, by pledging to give His life for us, Himself celebrated sacramentally the mystery of His passion and resurrection, the heart of every Mass.
Our Masses, being derived from thisliturgy, possess of themselves a complete liturgical form, which, in spite of its variations in line with the families of rites, remains substantially the same. The sacred character of the Mass is a sacredness instituted by Christ. The words and actions of every priest, answered by the conscious active participation of the whole eucharistic assembly, echo the words and actions of Holy Thursday.
The priest offers the holy Sacrifice in persona Christi; this means more than offering "in the name of' or "in place of' Christ. In persona means in specific sacramental identification with "the eternal High Priest"(42) who is the author and principal subject of this sacrifice of His, a sacrifice in which, in truth, nobody can take His place. Only He-only Christ-was able and is always able to be the true and effective "expiation for our sins and...for the sins of the whole world."(43) Only His sacrifice-and no one else's-was able and is able to have a "propitiatory power" be fore God, the Trinity, and the transcendent holiness. Awareness of this reality throws a certain light on the character and significance of the priest celebrant who, by confecting the holy Sacrifice and acting "in persona Christi," is sacramentally (and ineffably) brought into that most profound sacredness, and made part of it, spiritually linking with it in turn all those participating in the eucharistic assembly.
This sacred rite, which is actuated in different liturgical forms, may lack some secondary elements, but it can in no way lack its essential sacred character and sacramentality, since these are willed by Christ and transmitted and regulated by the Church. Neither can this sacred rite be utilized for other ends. If separated from its distinctive sacrificial and sacramental nature, the Eucharistic Mystery simply ceases to be. It admits of no "profane" imitation, an imitation that would very easily (indeed regularly) become a profanation. This must always be remembered, perhaps above all in our time, when we see a tendency to do away with the distinction between the "sacred" and "profane," given the widespread tendency, at least in some places, to desacralize everything.
In view of this fact, the Church has a special duty to safeguard and strengthen the sacredness of the Eucharist. In our pluralistic and often deliberately secularized society, the living faith of the Christiancommunity-a faith always aware of its rights vis-a-vis those who do not share that faith-ensures respect for this sacredness. The duty to respect each person's faith is the complement of the natural and civil right to freedom of conscience and of religion.
The sacred character of the Eucharist has found and continues to find expression in the terminology of theology and the liturgy.(44) This sense of the objective sacred character of the Eucharistic Mystery is so much part of the faith of the People of God that their faith is enriched and strengthened by it.(45) Therefore the ministers of the Eucharist must, especially today, be illumined by the fullness of this living faith, and in its light they must understand and perform all that is part, by Christ's will and the will of His Church, of their priestly ministry.