"I am the living bread that came down from heaven. . . Unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you" -- John 6:51, 53
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.
And finally, 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.
Before receiving the Eucharist, consider the following:
As Catholics, we fully participate in the celebration of the Eucharist when we receive Holy Communion. We are encouraged to receive Communion devoutly and frequently. In order to be properly disposed to receive Communion, participants should not be conscious of grave sin and normally should have fasted for one hour. A person who is conscious of grave sin is not to receive the Body and Blood of the Lord without prior sacramental confession except for a grave reason where there is no opportunity for confession. In this case, the person is to be mindful of the obligation to make an act of perfect contrition, including the intention of confessing as soon as possible (canon 916).
A frequent reception of the Sacrament of Penance is encouraged for all.
"As two pieces of wax fused together make one, so those who receive Holy Communion are so united with Christ that Christ is in them and they are in Christ" -- St. Cyril of Alexandria