20 What I say is that the things offered by the Gentiles are offered to evil spirits and not to God; and it is not my desire for you to have any part with evil spirits. 21 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.
Matthew Henry's Commentary on 1 Corinthians 10:20-21
Commentary on 1 Corinthians 10:15-22
(Read 1 Corinthians 10:15-22)
Did not the joining in the Lord's supper show a profession of faith in Christ crucified, and of adoring gratitude to him for his salvation ? Christians, by this ordinance, and the faith therein professed, were united as the grains of wheat in one loaf of bread, or as the members in the human body, seeing they were all united to Christ, and had fellowship with him and one another. This is confirmed from the Jewish worship and customs in sacrifice. The apostle applies this to feasting with idolaters. Eating food as part of a heathen sacrifice, was worshipping the idol to whom it was made, and having fellowship or communion with it; just as he who eats the Lord's supper, is accounted to partake in the Christian sacrifice, or as they who ate the Jewish sacrifices partook of what was offered on their altar. It was denying Christianity; for communion with Christ, and communion with devils, could never be had at once. If Christians venture into places, and join in sacrifices to the lust of the flesh, the lust of the eye, and the pride of life, they will provoke God.