Must we confess sin before eating the body and blood of Christ? What does "examine yourself" mean in I Corinthians 11:28?
The Lord's Supper is a memorial of Jesus' death. "For I received from the Lord that which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread; and when He had given thanks, He broke it and said, "Take, eat; this is My body which is broken for you; do this in remembrance of Me." In the same manner He also took the cup after supper, saying, "This cup is the new covenant in My blood. This do, as often as you drink it, in remembrance of Me." For as often as you eat this bread and drink this cup, you proclaim the Lord's death till He comes" (I Corinthians 11:23-26). It is not a meal dealing with our sins.
What Paul was condemning the Corinthians for doing is not treating this memorial in the solemn manner in which it deserved. "Therefore whoever eats the bread or drinks the cup of the Lord in an unworthy manner, shall be guilty of the body and the blood of the Lord. But a man must examine himself, and in so doing he is to eat of the bread and drink of the cup. For he who eats and drinks, eats and drinks judgment to himself if he does not judge the body rightly" (I Corinthians 11:27-29). Some misread this statement and think that Paul said we must be worthy of Christ's death. The truth of the matter is that no one is worthy of Christ's death on his behalf. But, regardless, what Paul said is that it is to be partaken of in a worthy manner. It is to be done in a manner worthy of what it represents -- the death of our Savior.
Understanding that then a person should examine himself and see if the way he is partaking of the Lord's Supper and the motivations in his mind is respectful to the memory of Christ's death on his behalf. If he shows disrespect ("does not judge the body rightly"), he brings condemnation on himself.