“Amen, amen, I say to you, unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you. Whoever eats my flesh and drinks my blood has eternal life, and I will raise him on the last day. For my flesh is true food, and my blood is true drink. Whoever eats my flesh and drinks my blood remains in me and I in him.”
The Eucharist is the “source and summit of the Christian Life” (Lumen Gentium, 11). It is the sacrament in which Christ is really and truly present under the appearances of bread and wine. The Sacrament of the Eucharist was described as follows by the Second Vatican Council:
At the Last Supper, on the night when he was betrayed, our Savior instituted the Eucharistic Sacrifice of his Body and Blood. He did this in order to perpetuate the Sacrifice of the Cross throughout the centuries until he should come again, and so to entrust to his beloved spouse, the Church, a memorial of his death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a paschal banquet in which Christ is consumed, the mind is filled with grace, and a pledge of future glory is given to us (Catechism of the Catholic Church 1322-1419).
The Effects of the Eucharist:
Unites the Recipient to Christ: The first effect of the Eucharist is to unite the recipient to Christ, for the Eucharist contains Christ himself. This union was what Christ promised in the Bread of Life Discourse (John 6:56).
Gives Life: For just as material food and drink assist in maintaining, improving, and building up our life, so too does the Eucharist — the “true food” and “true drink” — bestow life (John 6:54).
Gives a Share in the Life of Christ and the Trinity: The life that is nourished by the Eucharist extends to the spiritual life, to eternal life that will culminate in the future resurrection of the body (John 6:55).
Unites the Church: The social or communitarian aspect to the Eucharist builds up the mystical body of Christ. Just as the Christian faithful are united to each other in faith and baptism, so too are they united in Christ through the Eucharist (Catholic Bible Dictionary, 259).