At the heart of the Holy Eucharist are the bread and wine that, by the words of Christ and the invocation of the Holy Spirit, truly and substantially become the Body and Blood of the risen and glorified Lord Jesus. In the Old Covenant, bread and wine were offered in sacrifice among the first fruits of the earth as a sign of gratitude to God, but they also received a new meaning by the Exodus of Israel from slavery in Egypt.
The unleavened bread of Passover recalls the haste of departure on pilgrimage to the promised land, and manna in the desert testifies that God always fulfills His promise to sustain His people. Moreover, blood is the sign of fidelity to God's covenant with Israel and of sorrow for sins which violate God's law. The cup of blessing at the end of the Jewish Passover meal transforms the simple human joy in wine into a sign of God's saving action in history: the messianic expectation of the rebuilding of Jerusalem. All of these meanings were taken up and transformed by the Lord Jesus, the true Lamb of God, when He instituted the Holy Eucharist and commanded the Church to celebrate this sacrifice until He comes again in glory.
The Most Holy Eucharist is described in sections 1322-1412 of the Catechism of the Catholic Church, and we encourage every family to study these pages of the Catechism carefully in order to understand more deeply the inexhaustible riches of the sacred Mystery of Christ's Body and Blood.
In the other six sacraments, God gives us a gift of grace; in the Holy Mass He gives us the gift of Himself. That is why the Holy Eucharist is the Sacrament of sacraments, the Mystery of mysteries. The Lord Jesus urgently invites us to receive Him in this wondrous sacrament: "Truly, I say to you, unless you eat the flesh of the Son of man and drink His blood, you have no life in you" (John 6:53). Even as we struggle to understand this Mystery of Faith, we rejoice in this most sublime and abiding sacrifice of praise.