CIC 610 Jesus gave the supreme expression of his free offering of himself at the meal shared with the twelve Apostles “on the night he was betrayed”.1 On the eve of his Passion, while still free, Jesus transformed this Last Supper with the apostles into the memorial of his voluntary offering to the Father for the salvation of men: “This is my body which is given for you.” “This is my blood of the covenant, which is poured out for many for the forgiveness of sins.”2

CIC 611 The Eucharist that Christ institutes at that moment will be the memorial of his sacrifice.3 Jesus includes the apostles in his own offering and bids them perpetuate it.4 By doing so, the Lord institutes his apostles as priests of the New Covenant: “For their sakes I sanctify myself, so that they also may be sanctified in truth.”5

CIC 671 Though already present in his Church, Christ’s reign is nevertheless yet to be fulfilled “with power and great glory” by the King’s return to earth.6 This reign is still under attack by the evil powers, even though they have been defeated definitively by Christ’s Passover.7 Until everything is subject to him, “until there be realized new heavens and a new earth in which justice dwells, the pilgrim Church, in her sacraments and institutions, which belong to this present age, carries the mark of this world which will pass, and she herself takes her place among the creatures which groan and travail yet and await the revelation of the sons of God.”8 That is why Christians pray, above all in the Eucharist, to hasten Christ’s return by saying to him:9 Marana tha! “Our Lord, come!”10

CIC 781 “At all times and in every race, anyone who fears God and does what is right has been acceptable to him. He has, however, willed to make men holy and save them, not as individuals without any bond or link between them, but rather to make them into a people who might acknowledge him and serve him in holiness. He therefore chose the Israelite race to be his own people and established a covenant with it. He gradually instructed this people. .. All these things, however, happened as a preparation for and figure of that new and perfect covenant which was to be ratified in Christ. .. the New Covenant in his blood; he called together a race made up of Jews and Gentiles which would be one, not according to the flesh, but in the Spirit.”11

CIC 1076 The Church was made manifest to the world on the day of Pentecost by the outpouring of the Holy Spirit.12 The gift of the Spirit ushers in a new era in the “dispensation of the mystery” the age of the Church, during which Christ manifests, makes present, and communicates his work of salvation through the liturgy of his Church, “until he comes.”13 In this age of the Church Christ now lives and acts in and with his Church, in a new way appropriate to this new age. He acts through the sacraments in what the common Tradition of the East and the West calls “the sacramental economy”; this is the communication (or “dispensation”) of the fruits of Christ’s Paschal mystery in the celebration of the Church’s “sacramental” liturgy.
It is therefore important first to explain this “sacramental dispensation” (chapter one). The nature and essential features of liturgical celebration will then appear more clearly (chapter two).

CIC 1130 The Church celebrates the mystery of her Lord “until he comes,” when God will be “everything to everyone.”14 Since the apostolic age the liturgy has been drawn toward its goal by the Spirit’s groaning in the Church: Marana tha!15 The liturgy thus shares in Jesus’ desire: “I have earnestly desired to eat this Passover with you. .. until it is fulfilled in the kingdom of God.”16 In the sacraments of Christ the Church already receives the guarantee of her inheritance and even now shares in everlasting life, while “awaiting our blessed hope, the appearing of the glory of our great God and Savior Christ Jesus.”17 The “Spirit and the Bride say, ‘Come. .. Come, Lord Jesus!”’18
St. Thomas sums up the various aspects of sacramental signs: “Therefore a sacrament is a sign that commemorates what precedes it- Christ’s Passion; demonstrates what is accomplished in us through Christ’s Passion – grace; and prefigures what that Passion pledges to us – future glory.”19

CIC 1328 The inexhaustible richness of this sacrament is expressed in the different names we give it. Each name evokes certain aspects of it. It is called:
Eucharist, because it is an action of thanksgiving to God. The Greek words eucharistein20 and eulogein21 recall the Jewish blessings that proclaim – especially during a meal – God’s works: creation, redemption, and sanctification.

CIC 1329 The Lord’s Supper, because of its connection with the supper which the Lord took with his disciples on the eve of his Passion and because it anticipates the wedding feast of the Lamb in the heavenly Jerusalem.22
The Breaking of Bread, because Jesus used this rite, part of a Jewish meat when as master of the table he blessed and distributed the bread,23 above all at the Last Supper.24 It is by this action that his disciples will recognize him after his Resurrection,25 and it is this expression that the first Christians will use to designate their Eucharistic assemblies;26 by doing so they signified that all who eat the one broken bread, Christ, enter into communion with him and form but one body in him.27
The Eucharistic assembly (synaxis), because the Eucharist is celebrated amid the assembly of the faithful, the visible expression of the Church.28

CIC 1339 Jesus chose the time of Passover to fulfill what he had announced at Capernaum: giving his disciples his Body and his Blood:
Then came the day of Unleavened Bread, on which the passover lamb had to be sacrificed. So Jesus sent Peter and John, saying, “Go and prepare the passover meal for us, that we may eat it. ..” They went. .. and prepared the passover. And when the hour came, he sat at table, and the apostles with him. And he said to them, “I have earnestly desired to eat this passover with you before I suffer; for I tell you I shall not eat it again until it is fulfilled in the kingdom of God.”... And he took bread, and when he had given thanks he broke it and gave it to them, saying, “This is my body which is given for you. Do this in remembrance of me.” And likewise the cup after supper, saying, “This cup which is poured out for you is the New Covenant in my blood.”29

CIC 1344 Thus from celebration to celebration, as they proclaim the Paschal mystery of Jesus “until he comes,” the pilgrim People of God advances, “following the narrow way of the cross,”30 toward the heavenly banquet, when all the elect will be seated at the table of the kingdom.

CIC 1356 If from the beginning Christians have celebrated the Eucharist and in a form whose substance has not changed despite the great diversity of times and liturgies, it is because we know ourselves to be bound by the command the Lord gave on the eve of his Passion: “Do this in remembrance of me.”31

CIC 1366 The Eucharist is thus a sacrifice because it re-presents (makes present) the sacrifice of the cross, because it is its memorial and because it applies its fruit:
[Christ], our Lord and God, was once and for all to offer himself to God the Father by his death on the altar of the cross, to accomplish there an everlasting redemption. But because his priesthood was not to end with his death, at the Last Supper “on the night when he was betrayed,” [he wanted] to leave to his beloved spouse the Church a visible sacrifice (as the nature of man demands) by which the bloody sacrifice which he was to accomplish once for all on the cross would be re-presented, its memory perpetuated until the end of the world, and its salutary power be applied to the forgiveness of the sins we daily commit.32

CIC 1376 The Council of Trent summarizes the Catholic faith by declaring: “Because Christ our Redeemer said that it was truly his body that he was offering under the species of bread, it has always been the conviction of the Church of God, and this holy Council now declares again, that by the consecration of the bread and wine there takes place a change of the whole substance of the bread into the substance of the body of Christ our Lord and of the whole substance of the wine into the substance of his blood. This change the holy Catholic Church has fittingly and properly called transubstantiation.”33

CIC 1393 Holy Communion separates us from sin. The body of Christ we receive in Holy Communion is “given up for us,” and the blood we drink “shed for the many for the forgiveness of sins.” For this reason the Eucharist cannot unite us to Christ without at the same time cleansing us from past sins and preserving us from future sins:
For as often as we eat this bread and drink the cup, we proclaim the death of the Lord. If we proclaim the Lord’s death, we proclaim the forgiveness of sins. If, as often as his blood is poured out, it is poured for the forgiveness of sins, I should always receive it, so that it may always forgive my sins. Because I always sin, I should always have a remedy.34

CIC 1566 “It is in the Eucharistic cult or in the Eucharistic assembly of the faithful (synaxis) that they exercise in a supreme degree their sacred office; there, acting in the person of Christ and proclaiming his mystery, they unite the votive offerings of the faithful to the sacrifice of Christ their head, and in the sacrifice of the Mass they make present again and apply, until the coming of the Lord, the unique sacrifice of the New Testament, that namely of Christ offering himself once for all a spotless victim to the Father.”35 From this unique sacrifice their whole priestly ministry draws its strength.36

CIC 2772 From this unshakeable faith springs forth the hope that sustains each of the seven petitions, which express the groanings of the present age, this time of patience and expectation during which “it does not yet appear what we shall be.”37 The Eucharist and the Lord’s Prayer look eagerly for the Lord’s return, “until he comes.”38

1 Roman Missal, EP III; cf. Mt 26:20; I Cor 11:23.
2 Lk 22:19; Mt 26:28; cf. I Cor 5:7.
3 1 Cor 11:25.
4 Cf. Lk 22:19.
5 Jn 17:19; cf. Council of Trent: DS 1752; 1764.
6 Lk 21:27; cf. Mt 25:31.
7 Cf. 2 Th 2:7.
8 LG 48 # 3; cf. 2 Pt 3:13; Rom 8:19-22; I Cor 15:28.
9 Cf. I Cor 11:26; 2 Pt 3:11-12.
10 1 Cor 16:22; Rev 22:17,20.
11 LG 9; Cf. Acts 10:35; 1 Cor 11:25.
12 Cf. SC 6; LG 2.
13 1 Cor 11:26.
14 1 Cor 11:26; 15:28.
15 1 Cor 16:22.
16 Lk 22:15.
17 Titus 2:13.
18 Rev 22:17, 20.
19 St. Thomas Aquinas, STh III, 60, 3.
20 Cf. Lk 22:19; 1 Cor 11:24.
21 Cf. Mt 26:26; Mk 14:22.
22 Cf. 1 Cor 11:20; Rev 19:9.
23 Cf. Mt 14:19; 15:36; Mk 8:6, 19.
24 Cf. Mt 26:26; 1 Cor 11:24.
25 Cf. Lk 24:13-35.
26 Cf. Acts 2:42, 46; 20:7, 11.
27 Cf. 1 Cor 10:16-17.
28 Cf. 1 Cor 11:17-34.
29 Lk 22:7-20; Cf. Mt 26:17-29; Mk 14:12-25; 1 Cor 11:23-26.
30 AG 1; cf. 1 Cor 11:26.
31 1 Cor 11:24-25.
32 Council of Trent (1562): DS 1740; cf. 1 Cor 11:23; Heb 7:24, 27.
33 Council of Trent (1551): DS 1642; cf. Mt 26:26 ff.; Mk 14:22 ff.; Lk 22:19 ff.; 1 Cor 11:24 ff.
34 St. Ambrose, De Sacr. 4, 6, 28: PL 16, 446; cf. 1 Cor 11:26.
35 LG 28; cf. 1 Cor 11:26.
36 Cf. PO 2.
37 1 Jn 3:2; Cf. Col 3:4.
38 1 Cor 11:26.