At the Last Supper, on the night he was betrayed, Jesus Christ instituted the Eucharistic sacrifice of his Body and Blood. This he did in order to perpetuate the sacrifice of the cross throughout the ages until he should come again, and so to entrust to the Church a memorial of his death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a Paschal banquet. (Catechism of the Catholic Church, 1323)
The Eucharist is considered “the source and summit of the Christian life,” around which the other sacraments and ministries are oriented. During the Mass, we receive the body and blood of Christ (the Eucharist) into ourselves in the form of consecrated bread and wine.
The holy Eucharist completes Christian initiation. Those who have been raised to the dignity of the royal priesthood by Baptism, and configured more deeply to Christ by Confirmation, participate with the whole community in the Lord’s own sacrifice by means of the Eucharist. (CCC, 1322)