Jesus said: "I am the living bread that came down from heaven; if any one eats of this bread, he will live forever; ..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).3
The Holy Eucharist completes Christian initiation. Those who have received the sacraments of Baptism and Confirmation now participate with the whole community in the Lord's own sacrifice by means of the Eucharist. 1
The Holy Eucharist - the body and blood, soul and divinity, of Jesus Christ - was given to us by Christ so that we may enter into union with Christ Himself . 2
1 and 3, Part 2, Section 2, Article 3 The Sacrament of the Eucharist from Catechism of the Catholic Church for the United States of America 1944.
2 Catholic Encyclopedia