1 Cor 10
16 The cup of blessing that we bless,** is it not a participation in the blood of Christ?** The bread that we break, is it not a participation in the body of Christ?
17 Because the loaf of bread is one, we, though many, are one body, for we all partake of the one loaf.
1 Cor 11
23 For I received from the Lord what I also handed on to you,k that the Lord Jesus, on the night he was handed over, took bread, 24 and, after he had given thanks, broke it and said, “This is my body that 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 death of the Lord until he comes.
27 Therefore whoever eats the bread or drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord.
28 A person should examine himself, and so eat the bread and drink the cup.
29 For anyone who eats and drinks** without discerning the body**, eats and drinks judgment* on himself.
Christ told us that "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.” Jn 6:51
and that "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. 54 Whoever eats my flesh and drinks my blood has eternal life, and I will raise him on the last day. 55 For my flesh is true food, and my blood is true drink. Jn 6:53
He tells us these things right after the multiplication of the loaves and the fishes…where he provides nourishment for all…
…but we also see that this teaching was too hard for a number of disciples, who turned away from him.
Many do the same when they turn their back on the table of the Lord!