The Eucharist 1324 The Eucharist is "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."
1374 The mode of Christ's presence under the Eucharistic species is unique. It raises the Eucharist above all the sacraments as "the perfection of the spiritual life and the end to which all sacraments tend." In the most blessed sacrament of the Eucharist "the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained." "This presence is called 'real' - by which is not intended to exclude the other types of presence as if they could not be 'real' too, but because it is presence in the fullest sense: that is to say, it is a substantial presence by which Christ, God and man, makes himself wholly and entirely present."
am the bread of life. Your ancestors ate the manna in the desert, but
they died; this is the bread that comes down from heaven so that one
may eat it and not die. 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." The Jews quarreled among themselves, saying, "How can this man give us (his) flesh to eat?" Jesus said to them, "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. Just as
the living Father sent me and I have life because of the Father, so
also the one who feeds on me will have life because of me. This is the
bread that came down from heaven. Unlike your ancestors who ate and
still died, whoever eats this bread will live forever." These
things he said while teaching in the synagogue in Capernaum. Then many
of his disciples who were listening said, "This saying is hard; who can
accept it?" Since Jesus knew that his disciples were murmuring about
this, he said to them, "Does this shock you? What
if you were to see the Son of Man ascending to where he was before? It
is the spirit that gives life, while the flesh is of no avail. The
words I have spoken to you are spirit and life. But there are some of
you who do not believe." Jesus knew from the beginning the ones who would not believe and the one who would betray him. And he said,
"For this reason I have told you that no one can come to me unless it
is granted him by my Father." As a result of this, many (of) his
disciples returned to their former way of life and no longer
accompanied him. Jesus then said to the Twelve, "Do you also want to
leave?" Simon Peter answered him, "Master, to whom shall we go? You have the words of eternal life."