From the Gospel of St. John, chapter 6: 52-71…
52The Jews quarreled among themselves, saying, "How can this man give us [his] flesh to eat?"53Jesus 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.54Whoever east my flesh and drinks my blood has eternal life, and I will reais him on the last day.55For my flesh is true food, and my blood is true drink.56Whoever eats my flesh and drinks my blood remains in me and I in him.57Just 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.58 This is the bread that came down from heaven. Unlike your ancestors who ate and still died, whoever eats this bread will live forever."59These things he said while teaching in the synagogue in Capernaum.
60 Then many of his disciples who were listening said, "This saying is hard; who can accept it?61Since Jesus knew that his disciples were murmuring about this, he said to them, “Does this shock you?62What if you were to see the Son of Man ascending to where he was before?63It is the spirit that gives life, while the flesh is of no avail. The words I have spoken to you are spirit and life.64But 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.65And he said, “For this reason I have told you that no one can come to me unless it is granted him by my Father.”
66As a result of this, many [of] his disciples returned to their former way of life and no longer accompanied him.67Jesus then said to the Twelve, "Do you also want to leave?"68 Simon Peter answered him, Master, to whom shall we go? You have the words of eternal life.69We have come to believe and are convinced that you are the Holy One of God."70Jesus answered them, "Did I not choose you twelve? Yet is not one of you a devil?"71He was referring to Judas, son of Simon the Iscariot; it was he would betray him, one of the Twelve.