Eucharist
“The other sacraments, and indeed all ecclesiastical ministries and works of the apostolate, are bound up with the Eucharist and are oriented toward it.” (CCC 1324)
Jesus said:
“I am the living bread that came down from heaven; whoever eats this bread will live forever; and the bread that I will give is my flesh for the life of the world… Whoever eats my flesh and drinks my blood has eternal life, and I will raise him on the last day… Whoever eats my flesh and drinks my blood remains in me and I in him.”
(John 6:51, 54, 56)