You cannot drink the cup of the Lord, and the cup of demons: you cannot be partakers of the Lord's table, and of the table of demons.
All Commentaries on 1 Corinthians 10:21 Go To 1 Corinthians 10
Cyprian of Carthage
AD 258
Also the blessed apostle has said, "Ye cannot drink the cup of the Lord and the cup of devils; ye cannot be partakers of the Lord's table and of the table of devils.".
That we are not saying this dishonestly, our former letters have proved, wherein we have declared our opinion to you with a very plain statement, both against those who had betrayed themselves as unfaithful by the unlawful presentation of wicked certificates, as if they thought that they would escape those esnaring nets of the devil; whereas, not less than if they had approached to the wicked altars.
Also, the apostle testifies, and says, "Ye cannot drink the cup of the Lord and the cup of devils; ye cannot be partakers of the Lord's table and of the table of devils."