Let’s not base any understanding of the Eucharist on anything but the Bible. According to your belief a Christian-Jew would have to sin against one of the two presense of God, God of the OT, or Jesus in the NT. Jews were prohibited, by God, from drinking anything that contained it’s life blood. Even when they did sacrifices in the OT, they cut the throat of the animal, drained it off its life blood on the alter, and then cooked it up. This would be a contradiction of God’s own commandments. The NT did not void the OT.
Really? Let’s see exactly what the New Testament says about eating.
"10: And he called the people to him and said to them, “Hear and understand:
11: not what goes into the mouth defiles a man, but what comes out of the mouth, this defiles a man.” and further, "16: And he said, “Are you also still without understanding?
17: Do you not see that whatever goes into the mouth passes into the stomach, and so passes on?
18: But what comes out of the mouth proceeds from the heart, and this defiles a man.
19: For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander.
20: These are what defile a man; but to eat with unwashed hands does not defile a man.” (Matthew 15)
and yet again, 10: And he became hungry and desired something to eat; but while they were preparing it, he fell into a trance
11: and saw the heaven opened, and something descending, like a great sheet, let down by four corners upon the earth.
12: In it were all kinds of animals and reptiles and birds of the air.
13: And there came a voice to him, “Rise, Peter; kill and eat.”
14: But Peter said, “No, Lord; for I have never eaten anything that is common or unclean.”
15: And the voice came to him again a second time, “What God has cleansed, you must not call common.”
16: This happened three times, and the thing was taken up at once to heaven. (Acts 10)
and, 27: And he took a cup, and when he had given thanks he gave it to them, saying, "Drink of it, all of you;
28: for this is my blood of the covenant, which is poured out for many for the forgiveness of sins. (Matthew 26)
and, 23: And he took a cup, and when he had given thanks he gave it to them, and they all drank of it.
24: And he said to them, "This is my blood of the covenant, which is poured out for many. (Mark 14)
and, 23: For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread,
24: and when he had given thanks, he broke it, and said, “This is my body which is for you. Do this in remembrance of me.”
25: In the same way also the cup, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.”
26: For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes.
27: Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord.
28: Let a man examine himself, and so eat of the bread and drink of the cup.
29: For any one who eats and drinks without discerning the body eats and drinks judgment upon himself.
30: That is why many of you are weak and ill, and some have died. (1st Corinthains 11)
Now, you can continue to argue, but my question to you is, who will you obey? The teachings of modern men who have already been shown to deny that which the New Testament and the early church held so sacred (that they would not associate with anyone who denied it), or will you obey Our Lord Himself when he looks you in the eye and hands you the cup and says to you, “Drink of it, all of you; 28: for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.”
Pax domini sit semper vobiscum.