Preamble - A Witness to Unchanged Faith

22. The sacrificial nature of the Mass, solemnly asserted by the Council of Trent in accordance with the Church’s universal tradition,[1] was reaffirmed by the Second Vatican Council, which offered these significant words about the Mass: “At the Last Supper our Savior instituted the Eucharistic Sacrifice of his Body and Blood, by which he would perpetuate the Sacrifice of the Cross throughout the centuries until he should come again, thus entrusting to the Church, his beloved Bride, the memorial of his death and resurrection.”[2] What the Council thus teaches is expressed constantly in the formulas of the Mass. This teaching, which is concisely expressed in the statement already contained in the ancient Sacramentary commonly known as the Leonine“As often as the commemoration of this sacrifice is celebrated, the work of our redemption is carried out”[3]is aptly and accurately developed in the Eucharistic Prayers. For in these prayers the priest, while he performs the commemoration, turns towards God, even in the name of the whole people, renders him thanks and offers the living and holy Sacrifice, namely, the Church’s offering and the Victim by whose immolation God willed to be appeased;[4] and he prays that the Body and Blood of Christ may be a sacrifice acceptable to the Father and salvific for the whole world.[5] In this new Missal, then, the Church’s rule of prayer (lex orandi) corresponds to her perennial rule of belief (lex credendi), by which namely we are taught that the Sacrifice of the Cross and its sacramental renewal in the Mass, which Christ the Lord instituted at the Last Supper and commanded the Apostles to do in his memory, are one and the same, differing only in the manner of offering, and that consequently the Mass is at once a sacrifice of praise and thanksgiving, of propitiation and satisfaction.