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.” – Catechism of the Catholic Church 1322
“The Eucharist is ‘the source and summit of the Christian life.’ ‘The other sacraments, and indeed all ecclesiastical ministries and works of the apostolate, are bound up with the Eucharist and are oriented toward it. For in the blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself, our Pasch.'” –Catechism of the Catholic Church 1324
Jesus said: “I am the living bread that came down from heaven; if any one eats of this bread, he will live for ever;...he who eats my flesh and drinks my blood has eternal life and ...abides in me, and I in him” (Jn 6:51, 54, 56).