The Mass is a true sacrifice, not just a commemorative meal, as "Bible Christians" insist. The Fathers knew this.
"He took from among creation that which is bread, and gave thanks, saying, 'This is my body.' The cup likewise, which is from among the creation to which we belong, he confessed to be his blood. He taught the new sacrifice of the new covenant, of which Malachi, one of the twelve prophets, had signified beforehand: 'You do not do my will,' says the Lord Almighty, 'and I will not accept a sacrifice at your hands. For from the rising of the sun to its setting my name is glorified among the Gentiles, and in every place incense is offered to my name, and a pure sacrifice; for great is my name among the gentiles,' says the Lord Almighty. By these words he makes it plain that the former people will cease to make offerings to God; but that in every place sacrifice will be offered to him, and indeed, a pure one, for his name is glorified among the Gentiles" (Against Heresies 4:17:5 [inter A.D. 180-199]).
"If Christ Jesus, our Lord and God, is himself the high priest of God the Father; and if he offered himself as a sacrifice to the Father; and if he commanded that this be done in commemoration of himself, then certainly the priest, who imitates that which Christ did, truly functions in place of Christ" (Letter of Cyprian to a Certain Cecil 63:14 [circa A.D. 252]).
Cyril of Jerusalem
"Then, upon the completion of the spiritual sacrifice, the bloodless worship, over that propitiatory victim we call upon God for the common peace of the churches, for the welfare of the world, for kings, for soldiers and allies, for the sick, for the afflicted; and in summary, we all pray and offer this sacrifice for all who are in need" (Catechetical Lectures 23:Mystagogic 5:8 [A.D. 350]).
Gregory of Nazianz
"Cease not to pray and plead for me when you draw down the Word by your word, when in an unbloody cutting you cut the body and blood of the Lord, using your voice for a sword" (Letter of Gregory to Amphilochius, Bishop of Iconium 171 [circa A.D. 383]).
"When you see the Lord immolated and lying upon the altar, and the priest bent over that sacrifice praying, and all the people empurpled by that precious blood, can you think that you are still among men and on earth? Or are you not lifted up to heaven? (The Priesthood 3:4:177 [post A.D. 386]).
"Reverence, therefore, reverence this table, of which we are all communicants! Christ, slain for us, the Sacrificial Victim who is placed thereon! (Homilies on the Letter to the Romans 8:8 [circa A.D. 391]).
" 'The cup of blessing which we bless, is it not communion of the blood of Christ?' Very trustworthy and awesomely does he say it. For what he is saying is this: What is in the cup is that which flowed from his side, and we partake of it. He called it a cup of blessing because when we hold it in our hands that is how we praise him in song, wondering and astonished at his indescribable gift, blessing him because of his having poured out this very gift so that we might not remain in error; and not only for his having poured it out, but also for his sharing it with all of us. 'If therefore you desire blood,' he says, 'do not redden the platform of idols with the slaughter of dumb beasts, but my altar of sacrifice with my blood.' What is more awesome than this? What, pray tell, more tenderly loving?" (Homilies on the First Letter to the Corinthians 24:1(3) [circa A.D. 392]).
"In ancient times, because men were very imperfect, God did not scorn to receive the blood which they were offering to idols. He did this to draw them away from those idols; and this very thing again was because of his indescribable, tender affection. But now he has transferred the priestly action to what is most awesome and magnificent. He has changed the sacrifice itself, and instead of the butchering of dumb beasts, he commands the offering up of himself" (Ibid., 24:2).
"What then? Do we not offer daily? Yes, we offer, but making remem-brance of his death; and this remembrance is one and not many. How is it one and not many? Because this sacrifice is offered once, like that in the Holy of Holies. This sacrifice is a type of that, and this remembrance a type of that. We offer always the same, not one sheep now and another tomorrow, but the same thing always. Thus there is one sacrifice. By this reasoning, since the sacrifice is offered everywhere, are there, then, a multiplicity of Christs? By no means! Christ is one everywhere. He is complete here, complete there, one body. And just as he is one body and not many though offered everywhere, so too is there one sacrifice" (Homilies on the Letter to the Hebrews 17:3(6) [circa A.D. 403]).
"Accept therewith our hallowing too, as we say, 'Holy, holy, holy Lord Sabaoth, heaven and earth is full of your glory.' Heaven is full, and full is the earth, with your magnificent glory, Lord of Virtues. Full also is this sacrifice, with your strength and your communion; for to you we offer this living sacrifice, this unbloody oblation" (Anaphora or Prayer of the Eucharistic Sacrifice 13:12-16 [circa A.D. 350]).
"We saw the prince of priests coming to us, we saw and heard him offering his blood for us. We follow, inasmuch as we are able, being priests, and we offer the sacrifice on behalf of the people. Even if we are of but little merit, still, in the sacrifice, we are honorable. Even if Christ is not now seen as the one who offers the sacrifice, nevertheless it is he himself that is offered in sacrifice here on Earth when the body of Christ is offered. Indeed, to offer himself he is made visible in us, he whose word makes holy the sacrifice that is offered" (Commentaries on Twelve Psalms of David 38:25 [inter A.D. 381-397]).
"In the sacrament he is immolated for the people not only on every Easter Solemnity but on every day; and a man would not be lying if, when asked, he were to reply that Christ is being immolated. For if sacraments had not a likeness to those things of which they are sacraments, they would not be sacraments at all; and they generally take the names of those same things by reason of this likeness" (Letter to Boniface 98:9 [A.D. 408]).
"Open your eyes at last, then, any time, and see, from the rising of the sun to its setting, the sacrifice of Christians is offered, not in one place only, as was established with you Jews, but everywhere; and not to just any god at all, but to him who foretold it, the God of Israel. Not in one place, as was prescribed for you in the earthly Jerusalem, but in every place, even in Jerusalem herself. Not according to the order of Aaron, but according to the order of Melchizedek" (Sermon Against the Jews 9:13 [post A.D. 425]).
"Hold most firmly and never doubt in the least that the only-begotten God the Word himself become flesh [and] offered himself in an odor of sweetness as a sacrifice and victim to God on our behalf; to whom...in the time of the Old Testament animals were sacrificed by the patriarchs and prophets and priests; and to whom now, I mean in the time of the New Testament...the Holy Catholic Church does not cease in faith and love to offer throughout all the lands of the world a sacrifice of bread and wine. In those former sacrifices what would be given us in the future was signified figuratively, but in this sacrifice which has now been given us is shown plainly. In those former sacrifices it was fore-announced that the son of God would be killed for the impious, but in the present sacrifice it is announced that he has been killed for the impious" (The Rule of Faith 62 [inter A.D. 52.