1 Corinthians 11:27-28

11:27 For this reason, whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord. 11:28 A person should examine himself first, and in this way let him eat the bread and drink of the cup.

1 Corinthians 10:3-4

10:3 and all ate the same spiritual food, 10:4 and all drank the same spiritual drink. For they were all drinking from the spiritual rock that followed them, and the rock was Christ.

1 Corinthians 10:16-17

10:16 Is not the cup of blessing that we bless a sharing in the blood of Christ? Is not the bread that we break a sharing in the body of Christ? 10:17 Because there is one bread, we who are many are one body, for we all share the one bread.