1-corinthians 10:18

Behold Israel after the flesh - The Jews not yet converted to Christianity: the latter being Israel after the Spirit. As the design of the apostle was to withdraw his converts at Corinth from all temptations to idolatry, he produces two examples to show the propriety of his endeavors.

1. All who join together in celebrating the Lord's Supper, and are partakers of that one bread, give proof by this that they are Christians, and have fellowship with Christ.

2. All the Israelites who offer sacrifice, and partake of those sacrifices, give proof thereby that they are Jews, and are in fellowship with the object of their worship: so they who join in idol festivals, and eat things which have been offered to idols, give proof that they are in communion with those idolaters, and that they have fellowship with the demons they worship.

Behold Israel - Look at the Jews. The design here is to illustrate the sentiment which he was establishing, by a reference to the fact that among the Jews those who partook of the same sacrifices were regarded as being one people, and as worshipping one God. So, if they partook of the sacrifices offered to idols, they would be regarded also as being fellow-worshippers of idols with them.

After the flesh - See Romans 4:1. The phrase "after the flesh" is designed to denote the Jews who were not converted to Christianity; the natural descendants of Israel, or Jacob.

Are not they which eat of the sacrifices - A portion of the sacrifices offered to God was eaten by the offerer, and another portion by the priests. Some portions of the animal, as the fat, were burnt; and the remainder, unless it was a holocaust, or whole burnt-offering, was then the property of the priests who had officiated, or of the persons who had brought it; Exodus 29:13, Exodus 29:22; Lev, Leviticus 3:4, Leviticus 3:10, Leviticus 3:15; Leviticus 4:9; Leviticus 7:3-4; Leviticus 8:26. The right shoulder and the breast was the part which was assigned to the priests; the remainder belonged to the offerer.

Partakers of the altar - Worshippers of the same God. They are united in their worship, and are so regarded. And in like manner, if you partake of the sacrifices offered to idols, and join with their worshippers in their temples, you will be justly regarded as "united" with them in their worship, and partaking with them in their abominations.

10:18 Consider Israel after the flesh - Christians are the spiritual Israel of God. Are not they who eat of the sacrifices partakers of the altar - Is not this an act of communion with that God to whom they are offered? And is not the case the same with those who eat of the sacrifices which have been offered to idols?