1 Corinthians 11:23-28 NRSV
For I received from the Lord what I also handed on to you, that the Lord Jesus on the night when he was betrayed took a loaf of bread, and when he had given thanks, he broke it and said, “This is my body that is for you. Do this in remembrance of me.” In the same way he took the cup also, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.” For as often as you eat this bread and drink the cup, you proclaim the Lord's death until he comes.
Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be answerable for the body and blood of the Lord. Examine yourselves, and only then eat of the bread and drink of the cup.
NRSV: New Revised Standard Version