I Corinthians 11:26-29

For as often as you eat this bread and drink this cup, you proclaim the Lord’s death till He comes. Therefore whoever eats this bread or drinks this cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord. But let a man examine himself, and so let him eat of the bread and drink of the cup. For he who eats and drinks in an unworthy manner eats and drinks judgment to himself, not discerning the Lord’s body.