Today’s Catechism sections discuss the celebration of the Holy Mass. Supporting material comes from the Constitution on the Sacred Liturgy, “Sacrosanctum Concilium”.

IV. The Liturgical Celebration of the Eucharist

The Mass of all ages

1345 As early as the second century we have the witness of St. Justin Martyr for the basic lines of the order of the Eucharistic celebration. They have stayed the same until our own day for all the great liturgical families. St. Justin wrote to the pagan emperor Antoninus Pius (138-161) around the year 155, explaining what Christians did:

On the day we call the day of the sun, all who dwell in the city or country gather in the same place.
The memoirs of the apostles and the writings of the prophets are read, as much as time permits.
When the reader has finished, he who presides over those gathered admonishes and challenges them to imitate these beautiful things.
Then we all rise together and offer prayers* for ourselves . . .and for all others, wherever they may be, so that we may be found righteous by our life and actions, and faithful to the commandments, so as to obtain eternal salvation.
When the prayers are concluded we exchange the kiss.
Then someone brings bread and a cup of water and wine mixed together to him who presides over the brethren.
He takes them and offers praise and glory to the Father of the universe, through the name of the Son and of the Holy Spirit and for a considerable time he gives thanks (in Greek: eucharistian) that we have been judged worthy of these gifts.
When he has concluded the prayers and thanksgivings, all present give voice to an acclamation by saying: 'Amen.'
When he who presides has given thanks and the people have responded, those whom we call deacons give to those present the "eucharisted" bread, wine and water and take them to those who are absent.169

1346 The liturgy of the Eucharist unfolds according to a fundamental structure which has been preserved throughout the centuries down to our own day. It displays two great parts that form a fundamental unity:
- the gathering, the liturgy of the Word, with readings, homily and general intercessions;
- the liturgy of the Eucharist, with the presentation of the bread and wine, the consecratory thanksgiving, and communion.
The liturgy of the Word and liturgy of the Eucharist together form "one single act of worship";170 The Eucharistic table set for us is the table both of the Word of God and of the Body of the Lord.171

1347 Is this not the same movement as the Paschal meal of the risen Jesus with his disciples? Walking with them he explained the Scriptures to them; sitting with them at table "he took bread, blessed and broke it, and gave it to them."172

IN BRIEF

1408 The Eucharistic celebration always includes: the proclamation of the Word of God; thanksgiving to God the Father for all his benefits, above all the gift of his Son; the consecration of bread and wine; and participation in the liturgical banquet by receiving the Lord's body and blood. These elements constitute one single act of worship.

1409 The Eucharist is the memorial of Christ's Passover, that is, of the work of salvation accomplished by the life, death, and resurrection of Christ, a work made present by the liturgical action.

The Constitution on the Sacred Liturgy, “Sacrosanctum Concilium” (56) discusses the unity of the liturgy of the word and the liturgy of the Eucharist.

56. The two parts which, in a certain sense, go to make up the Mass, namely, the liturgy of the word and the Eucharistic liturgy, are so closely connected with each other that they form but one single act of worship. Accordingly this sacred Synod strongly urges pastors of souls that, when instructing the faithful, they insistently teach them to take their part in the entire Mass, especially on Sundays and feasts of obligation.

Footnotes

169 St. Justin, Apol. 1, 65-67: PG 6, 428-429; the text before the asterisk (*) is from chap. 67.
170 SC 56.
171 Cf. DV 21.
172 Cf. ⇒ Lk 24:13-35.