1 Corinthians 10:21
You cannot drink the Lord's cup and the cup of demons; you cannot partake at the Lord's table and the table of demons.
Matthew 6:24
No one can serve two masters; for either he will hate the first, and love the other, or he will adhere to the first, and despise the other. You cannot serve God and riches.
1 Corinthians 8:10
For if any one sees you who have knowledge reclining in an idol's temple, will not the conscience of him that is weak be emboldened to eat things offered to idols?
1 Corinthians 10:16
The cup of blessing which we bless, is it not a participation of the blood of Christ? The bread which we break, is it not a participation of the body of Christ?
2 Corinthians 6:15-17
and what agreement has Christ with Beliar, or what part has a believer with an unbeliever?