1 Corinthians 10:16-20 The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ? For we, though many, are one bread and one body; for we all partake of that one bread. Observe Israel after the flesh: Are not those who eat of the sacrifices partakers of the altar? What am I saying then? That an idol is anything, or what is offered to idols is anything? Rather, that the things which the Gentiles sacrifice they sacrifice to demons and not to God, and I do not want you to have fellowship with demons.
2 Corinthians 6:14-18 Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness? And what accord has Christ with Belial? Or what part has a believer with an unbeliever? And what agreement has the temple of God with idols? For you are the temple of the living God. As God has said: "I will dwell in them And walk among them. I will be their God, And they shall be My people." Therefore"Come out from among them And be separate, says the Lord. Do not touch what is unclean, And I will receive you." "Iwill be a Father to you, And you shall be Mysons and daughters, Says the LORD Almighty."
1 Corinthians 11:25-26 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.
1 John 1:3 that which we have seen and heard we declare to you, that you also may have fellowship with us; and truly our fellowship is with the Father and with His Son Jesus Christ.