Obj. 7: Further, the Divine power works this sacrament unfailingly. Therefore it is to no purpose that the priest asks for the perfecting of this sacrament, saying: "Which oblation do thou, O God, in all," etc.
Obj. 8: Further, the sacrifice of the New Law is much more excellent than the sacrifice of the fathers of old. Therefore, it is unfitting for the priest to pray that this sacrifice may be as acceptable as the sacrifice of Abel, Abraham, and Melchisedech.
Objection 9: Further, just as Christ's body does not begin to be in this sacrament by change of place, as stated above (Q. 75, A. 2), so likewise neither does it cease to be there. Consequently, it is improper for the priest to ask: "Bid these things be borne by the hands of thy holy angel unto Thine altar on high."
On the contrary, We find it stated in De Consecr., dist. 1, that "James, the brother of the Lord according to the flesh, and Basil, bishop of Caesarea, edited the rite of celebrating the mass": and from their authority it is manifest that whatever words are employed in this matter, are chosen becomingly.
I answer that, Since the whole mystery of our salvation is comprised in this sacrament, therefore is it performed with greater solemnity than the other sacraments. And since it is written (Eccles. 4:17): "Keep thy foot when thou goest into the house of God"; and (Ecclus. 18:23): "Before prayer prepare thy soul," therefore the celebration of this mystery is preceded by a certain preparation in order that we may perform worthily that which follows after. The first part of this preparation is Divine praise, and consists in the "Introit": according to Ps. 49:23: "The sacrifice of praise shall glorify me; and there is the way by which I will show him the salvation of God": and this is taken for the most part from the Psalms, or, at least, is sung with a Psalm, because, as Dionysius says (Eccl. Hier. iii): "The Psalms comprise by way of praise whatever is contained in Sacred Scripture."
The second part contains a reference to our present misery, by reason of which we pray for mercy, saying: "Lord, have mercy on us," thrice for the Person of the Father, and "Christ, have mercy on us," thrice for the Person of the Son, and "Lord, have mercy on us," thrice for the Person of the Holy Ghost; against the threefold misery of ignorance, sin, and punishment; or else to express the "circuminsession" of all the Divine Persons.
The third part commemorates the heavenly glory, to the possession of which, after this life of misery, we are tending, in the words, "Glory be to God on high," which are sung on festival days, on which the heavenly glory is commemorated, but are omitted in those sorrowful offices which commemorate our unhappy state.
The fourth part contains the prayer which the priest makes for the people, that they may be made worthy of such great mysteries.
There precedes, in the second place, the instruction of the faithful, because this sacrament is "a mystery of faith," as stated above (Q. 78, A. 3, ad 5). Now this instruction is given "dispositively," when the Lectors and Sub-deacons read aloud in the church the teachings of the prophets and apostles: after this "lesson," the choir sing the "Gradual," which signifies progress in life; then the "Alleluia" is intoned, and this denotes spiritual joy; or in mournful offices the "Tract", expressive of spiritual sighing; for all these things ought to result from the aforesaid teaching. But the people are instructed "perfectly" by Christ's teaching contained in the Gospel, which is read by the higher ministers, that is, by the Deacons. And because we believe Christ as the Divine truth, according to John 8:46, "If I tell you the truth, why do you not believe Me?" after the Gospel has been read, the "Creed" is sung in which the people show that they assent by faith to Christ's doctrine. And it is sung on those festivals of which mention is made therein, as on the festivals of Christ, of the Blessed Virgin, and of the apostles, who laid the foundations of this faith, and on other such days.
So then, after the people have been prepared and instructed, the next step is to proceed to the celebration of the mystery, which is both offered as a sacrifice, and consecrated and received as a sacrament: since first we have the oblation; then the consecration of the matter offered; and thirdly, its reception.