The existence of the Mass
Before dealing with the proofs of revelation afforded by the Bible and tradition, certain preliminary points must first be decided. Of these the most important is that the Church intends the Mass to be regarded as a “true and proper sacrifice”, and will not tolerate the idea that the sacrifice is identical with Holy Communion. That is the sense of a clause from the Council of Trent (Sess. XXII, can. 1): “If any one saith that in the Mass a true and proper sacrifice is not offered to God; or, that to be offered is nothing else but that Christ is given us to eat; let him be anathema” (Denzinger, “Enchir.”, 10th ed. 1908, n. 948). When Leo XIII in the dogmatic Bull “Apostolicae Curae” of 13 Sept., 1896, based the invalidity of the Anglican form of consecration on the fact among others, that in the consecrating formula of Edward VI (that is, since 1549) there is nowhere an unambiguous declaration regarding the Sacrifice of the Mass, the Anglican archbishops answered with some irritation: “First, we offer the Sacrifice of praise and thanksgiving; next, we plead and represent before the Father the Sacrifice of the Cross . . . and, lastly, we offer the Sacrifice of ourselves to the Creator of all things, which we have already signified by the oblation of His creatures. This whole action, in which the people has necessarily to take part with the priest, we are accustomed to call the communion, the Eucharistic Sacrifice”. In regard to this last contention, Bishop Hedley of Newport declared his belief that not one Anglican in a thousand is accustomed to call the communion the “Eucharistic Sacrifice.” But even if they were all so accustomed, they would have to interpret the terms in the sense of the thirty-nine Articles, which deny both the Real Presence and the sacrifical power of the priest, and thus admit a sacrifice in an unreal or figurative sense only. Leo XIII, on the other hand, in union with the whole Christian past, had in mind in the above-mentioned Bull nothing else than the Eucharistic “Sacrifice of the true Body and Blood of Christ” on the altar. This Sacrifice is certainly not identical with the Anglican form of celebration.
The simple fact that numerous heretics, such as Wyclif and Luther, repudiated the Mass as “idolatry”, while retaining the Sacrament of the true Body and Blood of Christ, proves that the Sacrament of the Eucharist is something essentially different from the Sacrifice of the Mass. In truth, the Eucharist performs at once two functions: that of a sacrament and that of a sacrifice. Though the inseparableness of the two is most clearly seen in the fact that the consecrating sacrificial powers of the priest coincide, and consequently that the sacrament is produced only in and through the Mass, the real difference between them is shown in that the sacrament is intended privately for the sanctification of the soul, whereas the sacrifice serves primarily to glorify God by adoration, thanksgiving, prayer, and expiation. The recipient of the one is God, who receives the sacrifice of His only-begotten Son; of the other, man, who receives the sacrament for his own good. Furthermore, the unbloody Sacrifice of the Eucharistic Christ is in its nature a transient action, while the Sacrament of the Altar continues as something permanent after the sacrifice, and can even be preserved in monstrance and ciborium. Finally, this difference also deserves mention: communion under one form only is the reception of the whole sacrament, whereas, without the use of the two forms of bread and wine (the symbolic separation of the Body and Blood), the mystical slaying of the victim, and therefore the Sacrifice of the Mass, does not take place.
The definition of the Council of Trent supposes as self-evident the proposition that, along with the “true and real Sacrifice of the Mass”, there can be and are in Christendom figurative and unreal sacrifices of various kinds, such as prayers of praise and thanksgiving, alms, mortification, obedience, and works of penance. Such offerings are often referred to in Holy Scripture, e.g. in Ecclesiasticus 35:4: “All he that doth mercy offereth sacrifice”; and in Psalm 140:2: “Let my prayer be directed as incense in thy sight, the lifting up of my hands as evening sacrifice.” These figurative offerings, however, necessarily presuppose the real and true offering, just as a picture presupposes its subject and a portrait its original. The Biblical metaphors – a “sacrifice of jubilation” (Ps. xxvi, 6), the "calves of our lips (Hosea 14:3), the “sacrifice of praise” (Hebrews 13:15) – expressions which apply sacrificial terms to sacrifice (hostia, thysia). That there was such a sacrifice, the whole sacrificial system of the Old Law bears witness. It is true that we may and must recognize with St. Thomas (II-II:85:3), as the principale sacrificium the sacrificial intent which, embodied in the spirit of prayer, inspires and animates the external offerings as the body animates the soul, and without which even the most perfect offering has neither worth nor effect before God. Hence, the holy psalmist says: “For if thou hadst desired sacrifice, I would indeed have given it: with burnt-offerings thou wilt not be delighted. A sacrifice to God is an afflicted spirit” (Ps. I, 18 sq.). This indispensable requirement of an internal sacrifice, however, by no means makes the external sacrifice superfluous in Christianity; indeed, without a perpetual oblation deriving its value from the sacrifice once offered on the Cross, Christianity, the perfect religion, would be inferior not only to the Old Testament, but even to the poorest form of natural religion. Since sacrifice is thus essential to religion, it is all the more necessary for Christianity, which cannot otherwise fulfil its duty of showing outward honour to God in the most perfect way.