1 Corinthians 10:18 - Joseph Benson’s Commentary on the Old and New Testaments

Behold Consider, by way of illustration; Israel after the flesh How it is with the present Jews, the natural descendants of Jacob, who worship God by sacrifices, according to the Mosaic law. He says, after the flesh, to distinguish them from the spiritual Israel, consisting of believers of all nations, called the Israel of God, Galatians 6:16. Are not they who eat of the sacrifices Who feast upon the remainders of the sacrifices offered at the altar; see Leviticus 7:15; 1 Samuel 1:4-5; partakers of the altar Do they not join in the worship there performed, and own the God there worshipped? And is not this an act of communion with that God to whom such sacrifices are offered? And is not the case the same with those who eat of the sacrifices offered to idols? This argument, drawn from the sentiments of the Jews, was used with peculiar propriety, especially in reasoning with the false teachers at Corinth, who, it seems, were Jews, and who, to ingratiate themselves with the Corinthians, are supposed to have encouraged them to eat of the idol's sacrifices.