The cup of blessing which we take, does it not give us a part in the blood of Christ? and is not the broken bread a taking part in the body of Christ?
1 Corinthians 10:16
It is not possible for you, at the same time, to take the cup of the Lord and the cup of evil spirits; you may not take part in the table of the Lord and the table of evil spirits.
1 Corinthians 10:21