“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.
We have come to believe and are convinced that you are the Holy One of God.”
Jesus answered them, “Did I not choose you twelve? Yet is not one of you a devil?”
He was referring to Judas, son of Simon the Iscariot; it was he who would betray him, one of the Twelve.” [John 6: 49-71]
You omitted the most important passages before the similtude:
John 6:26-47 NASB
Jesus answered them and said, “Truly, truly, I say to you, you seek Me, not because you saw signs, but because you ate of the loaves and were filled. Do not work for the food which perishes, but for the food which endures to eternal life, which the Son of Man will give to you, for on Him the Father, God, has set His seal.”
Therefore they said to Him, “What shall we do, so that we may work the works of God?” Jesus answered and said to them, “This is the work of God, that you believe in Him whom He has sent.” So they said to Him, “What then do You do for a sign, so that we may see, and believe You? What work do You perform? Our fathers ate the manna in the wilderness; as it is written, ‘H e gave them bread out of heaven to eat .’” Jesus then said to them, “Truly, truly, I say to you, it is not Moses who has given you the bread out of heaven, but it is My Father who gives you the true bread out of heaven.
For the bread of God is that which comes down out of heaven, and gives life to the world.” Then they said to Him, “Lord, always give us this bread.” Jesus said to them, “I am the bread of life; he who comes to Me will not hunger, and he who believes in Me will never thirst. But I said to you that you have seen Me, and yet do not believe. All that the Father gives Me will come to Me, and the one who comes to Me I will certainly not cast out. For I have come down from heaven, not to do My own will, but the will of Him who sent Me. This is the will of Him who sent Me, that of all that He has given Me I lose nothing, but raise it up on the last day. For this is the will of My Father, that everyone who beholds the Son and believes in Him will have eternal life, and I Myself will raise him up on the last day.”
Therefore the Jews were grumbling about Him, because He said, “I am the bread that came down out of heaven.” They were saying, “Is not this Jesus, the son of Joseph, whose father and mother we know? How does He now say, ‘I have come down out of heaven’ ?” Jesus answered and said to them, “Do not grumble among yourselves. No one can come to Me unless the Father who sent Me draws him; and I will raise him up on the last day. It is written in the prophets, ‘A nd they shall all be taught of G od .’ Everyone who has heard and learned from the Father, comes to Me. Not that anyone has seen the Father, except the One who is from God; He has seen the Father. Truly, truly, I say to you, he who believes has eternal life.