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.1
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,2 above all at the Last Supper.3 It is by this action that his disciples will recognize him after his Resurrection,4 and it is this expression that the first Christians will use to designate their Eucharistic assemblies;5 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.6
The Eucharistic assembly (synaxis), because the Eucharist is celebrated amid the assembly of the faithful, the visible expression of the Church.7

CIC 1334 In the Old Covenant bread and wine were offered in sacrifice among the first fruits of the earth as a sign of grateful acknowledgment to the Creator. But they also received a new significance in the context of the Exodus: the unleavened bread that Israel eats every year at Passover commemorates the haste of the departure that liberated them from Egypt; the remembrance of the manna in the desert will always recall to Israel that it lives by the bread of the Word of God;8 their daily bread is the fruit of the promised land, the pledge of God’s faithfulness to his promises. The “cup of blessing”9 at the end of the Jewish Passover meal adds to the festive joy of wine an eschatological dimension: the messianic expectation of the rebuilding of Jerusalem. When Jesus instituted the Eucharist, he gave a new and definitive meaning to the blessing of the bread and the cup.

CIC 1396 The unity of the Mystical Body: the Eucharist makes the Church. Those who receive the Eucharist are united more closely to Christ. Through it Christ unites them to all the faithful in one body – the Church. Communion renews, strengthens, and deepens this incorporation into the Church, already achieved by Baptism. In Baptism we have been called to form but one body.10 The Eucharist fulfills this call: “The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread:”11
If you are the body and members of Christ, then it is your sacrament that is placed on the table of the Lord; it is your sacrament that you receive. To that which you are you respond “Amen” (“yes, it is true!”) and by responding to it you assent to it. For you hear the words, “the Body of Christ” and respond “Amen.” Be then a member of the Body of Christ that your Amen may be true.12

CIC 1621 In the Latin Rite the celebration of marriage between two Catholic faithful normally takes place during Holy Mass, because of the connection of all the sacraments with the Paschal mystery of Christ.13 In the Eucharist the memorial of the New Covenant is realized, the New Covenant in which Christ has united himself for ever to the Church, his beloved bride for whom he gave himself up.14 It is therefore fitting that the spouses should seal their consent to give themselves to each other through the offering of their own lives by uniting it to the offering of Christ for his Church made present in the Eucharistic sacrifice, and by receiving the Eucharist so that, communicating in the same Body and the same Blood of Christ, they may form but “one body” in Christ.15

1 Cf. 1 Cor 11:20; Rev 19:9.
2 Cf. Mt 14:19; 15:36; Mk 8:6, 19.
3 Cf. Mt 26:26; 1 Cor 11:24.
4 Cf. Lk 24:13-35.
5 Cf. Acts 2:42, 46; 20:7, 11.
6 Cf. 1 Cor 10:16-17.
7 Cf. 1 Cor 11:17-34.
8 Cf. Deut 8:3.
9 1 Cor 10:16.
10 Cf. 1 Cor 12:13.
11 1 Cor 10:16-17.
12 St. Augustine, Sermo 272: PL 38, 1247.
13 Cf. SC 61.
14 Cf. LG 6.
15 Cf. 1 Cor 10:17.