The Mass, or Celebration of the Eucharist, represents the principal liturgical action in the Roman Catholic Church. From the earliest days of Christianity through today, communities of believers, many parts of the one body of Christ, to celebrate God’s gifts to us and receive Jesus true presence in the form of bread and wine. Participating in the Holy Sacrifice of Mass nourishes and heals of all worshipers together. It is not the priest “performing” for the people, but it is the community of faith, priest and people alike, worshiping, praising, and celebrating together as One Body and Blood of Christ. The Lord Jesus gave us the Eucharist at the Last Supper on the night before He died for us. In this celebration, we participate in the mystery of salvation by remembering the sacrificial death and resurrection of the Lord.

When we gather to celebrate Mass what we see already gives us a clue of what we do.
At the centre of the space intended for the celebration there is an altar, which is a table covered with a tablecloth, and this suggests to us a banquet.
At the table there is a cross to indicate that on this altar what is offered is the sacrifice of Christ: he is the spiritual food that we receive there, under the species of bread and wine.
Beside the table is the ambo, the place from which the Word of God is proclaimed: and this indicates that there we gather to listen to the Lord who speaks through Sacred Scripture, and therefore the food that we receive is also his Word.

Word and Bread in the Mass become one, as at the Last Supper, when all the words of Jesus, all the signs that he had performed, were condensed into the gesture of breaking the bread and offering the chalice, in anticipation of the sacrifice of the cross, and in these words: “Take, eat; this is my body… Take, drink of it; for this is my blood”.

The Eucharist is the source and summit of the Church’s life. (Lumen Gentium 11)

The Eucharist also brings about the unity which is represented, gathering the faithful into one Body the Church and uniting us with God the Father through the reception of Christ’s Body and Blood. (Unitatis Redintegratio No 2)

The Eucharist is a foretaste of what awaits the believer in Heaven, when united with other believers he will behold God face-to-face. (Gaudium et Spes, No 38)

The other sacraments, as well as every ministry of the Church and every work of the apostolate, are linked with the holy Eucharist and are directed toward it. (Presybterorum Ordinis No 5)

“It is so important to go to Mass on Sunday,” not just to pray, but to receive Communion. It is a beautiful thing to do for Sunday is precisely the day of the resurrection of the Lord. That is why Sunday is so important to us.”
Pope Francis 5 February 2014