Eucharist is Biblically based:
Mark 14:22-24
22 And as they were eating, he took bread, and blessed, and broke it, and gave it to them, and said, “Take; this is my body.” 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.
Luke 22:19-20
19 And he took bread, and when he had given thanks he broke it and gave it to them, saying, “This is my body which is given for you. Do this in remembrance of me.” 20 And likewise the cup after supper, saying, “This cup which is poured out for you is the new covenant in my blood.
John 6:51
51 I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh.”
John 6:53
53 So Jesus said to them, “Truly, truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you;
1 Corinthians 10:16
16 The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ?