Are you sure that the doubters believe?
From the posters here, many do not believe in the Real Presence of Jesus in the Eucharist. Many posters can quote scripture without the full message.
The rest of the story (John 6:53-70)
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. 54Whoever eats* my flesh and drinks my blood has eternal life, and I will raise 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.b 58This 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.
The Words of Eternal Life.* 60Then 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.c 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?” 68Simon 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.”d 70Jesus answered them, “Did I not choose you twelve? Yet is not one of you a devil?”
Blows the whole * must eat the literal flesh and blood of Jesus to have eternal life* interpretation out of the water.
Right there He says Himself the the SPIRIT gives life, the flesh is no help at all.
Eating the flesh is NOT going to help.
Don't you believe the words of Jesus?
And why ignore the whole Bible's worth of prohibition against eating blood?
In the OT sacrifices that foreshadowed the sacrifice of Jesus, the blood was NEVER to be eaten, and it is one of the few OT prohibitions reiterated to the church at the Council of Jerusalem.
Don't eat the blood, the life is in the blood
Genesis 9:4 But you shall not eat flesh with its life , that is, its blood.
Leviticus 3:17 It shall be a statute forever throughout your generations, in all your dwelling places, that you eat neither fat nor blood.”
Leviticus 7:26-27 Moreover, you shall eat no blood whatever, whether of fowl or of animal, in any of your dwelling places. Whoever eats any blood, that person shall be cut off from his people.”
Leviticus 17:10-14 “If any one of the house of Israel or of the strangers who sojourn among them eats any blood, I will set my face against that person who eats blood and will cut him off from among his people. For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life. Therefore I have said to the people of Israel, No person among you shall eat blood, neither shall any stranger who sojourns among you eat blood.
“Any one also of the people of Israel, or of the strangers who sojourn among them, who takes in hunting any beast or bird that may be eaten shall pour out its blood and cover it with earth. For the life of every creature is its blood: its blood is its life. Therefore I have said to the people of Israel, You shall not eat the blood of any creature, for the life of every creature is its blood. Whoever eats it shall be cut off.
Leviticus 19:26 “You shall not eat any flesh with the blood in it. You shall not interpret omens or tell fortunes.
Deuteronomy 12:16 Only you shall not eat the blood ; you shall pour it out on the earth like water.
Deuteronomy 12:23 Only be sure that you do not eat the blood, for the blood is the life , and you shall not eat the life with the flesh.
Deuteronomy 15:23 Only you shall not eat its blood; you shall pour it out on the ground like water.
Acts 15:12-29 And all the assembly fell silent, and they listened to Barnabas and Paul as they related what signs and wonders God had done through them among the Gentiles. After they finished speaking, James replied, “Brothers, listen to me. Simeon has related how God first visited the Gentiles, to take from them a people for his name. And with this the words of the prophets agree, just as it is written,
“‘After this I will return, and I will rebuild the tent of David that has fallen; I will rebuild its ruins, and I will restore it, that the remnant of mankind may seek the Lord, and all the Gentiles who are called by my name, says the Lord, who makes these things known from of old.’
Therefore my judgment is that we should not trouble those of the Gentiles who turn to God, but should write to them to abstain from the things polluted by idols, and from sexual immorality, and from what has been strangled, and from blood. For from ancient generations Moses has had in every city those who proclaim him, for he is read every Sabbath in the synagogues.”
Then it seemed good to the apostles and the elders, with the whole church, to choose men from among them and send them to Antioch with Paul and Barnabas. They sent Judas called Barsabbas, and Silas, leading men among the brothers, with the following letter:
“The brothers, both the apostles and the elders, to the brothers who are of the Gentiles in Antioch and Syria and Cilicia, greetings. Since we have heard that some persons have gone out from us and troubled you with words, unsettling your minds, although we gave them no instructions, it has seemed good to us, having come to one accord, to choose men and send them to you with our beloved Barnabas and Paul, men who have risked their lives for the name of our Lord Jesus Christ. We have therefore sent Judas and Silas, who themselves will tell you the same things by word of mouth. For it has seemed good to the Holy Spirit and to us to lay on you no greater burden than these requirements: that you abstain from what has been sacrificed to idols, and from blood, and from what has been strangled, and from sexual immorality. If you keep yourselves from these, you will do well. Farewell.”
Matthew 26:29 I tell you I will not drink again of this fruit of the vine until that day when I drink it new with you in my Father’s kingdom.”
Mark 14:25 Truly, I say to you, I will not drink again of the fruit of the vine until that day when I drink it new in the kingdom of God.”
Luke 22:18 For I tell you that from now on I will not drink of the fruit of the vine until the kingdom of God comes.”
John 6:63 It is the Spirit who gives life; the flesh is no help at all. The words that I have spoken to you are spirit and life.
Jesus could not have broken the Law and could not have demanded that people break the Law by demanding that they eat blood.
One comes to Christ through faith in Him.
Get thee behind Me; Satan.
If you had the spark of the Spirit of God in you, when you read the passage from John 6 and the scenes from Matthew, Luke, and Mark where Jesus instituted the Shift in the Passover Seder to be a Remembrance of Him (it had been a remembrance of what God did for the Israelites in bringing them out of Egypt!), you would instinctively know JESUS as GOD with us would not violate the very Laws He established, and you would partake in the REMEMBRANCE thanking GOD for what JESUS did ONCE for ALL, forever.
Jesus established the concept of His real Presence, not so He could be swallowed in a pagan ritual but as a means for those faithing in HIM to receive the REAL empowerment where two or more are gathered in HIS name, for there is HE in the midst of them!