Paul now deals directly with the problem of idol sacrifice. He appeals to the analogy of the Supper. The Eucharistic cup brings the worshipper into fellowship with Christ's blood, the loaf into fellowship with His body. Participating in the one loaf the many worshippers become one. So the eating of the Israelite sacrifices effects communion with the altar (so Philo, not OT). Let these analogies be applied. Neither the sacrifice nor the idol are real. But the sacrifices are offered to the demons not to God (Deuteronomy 32:17), and thus bring the participants into fellowship with demons. This involves an intolerable incompatibility; they cannot combine the Lord's cup and table with those of the demons. What madness to rouse the Lord's jealousy by giving Him such a rival (Deuteronomy 32:21)! are the strong stronger than He?
1 Corinthians 10:14-22
14 Wherefore, my dearly beloved, flee from idolatry.
15 I speak as to wise men; judge ye what I say.
16 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?
17 For we being many are one bread, and one body: for we are all partakers of that one bread.
18 Behold Israel after the flesh: are not they which eat of the sacrifices partakers of the altar?
19 What say I then? that the idol is any thing, or that which is offered in sacrifice to idols is any thing?
20 But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils.
21 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.
22 Do we provoke the Lord to jealousy? are we stronger than he?