Paul adds a second example the Corinthians could check for themselves: Israel's sacrifices. Barnes explains that among the Jews, those who ate of the same sacrifices "were regarded as being one people, and as worshipping one God." The question presses the Corinthians to admit that eating a sacrifice is not a neutral meal. It joins the eater to the altar and to the God worshipped there. That prepares them for Paul's point about idol feasts (1 Corinthians 10:20-21).

Paul does not stop to answer, because the answer is obviously yes. He moves to the objection his reasoning might raise, "What say I then? that the idol is any thing?" (1 Corinthians 10:19), and then gives the conclusion: what the Gentiles sacrifice, "they sacrifice to devils," and "I would not that ye should have fellowship with devils" (1 Corinthians 10:20).

Under the Law, some offerings were partly eaten by the worshippers, such as the flesh of the peace offerings, which "shall be eaten the same day that it is offered" (Leviticus 7:15). Barnes points to the Law's instructions about the parts burned on the altar (for example Leviticus 3:4). "Israel after the flesh" means the nation of Israel by natural descent. Gill says Paul uses the phrase to distinguish them "from the Israel of God, the spiritual Israel" (see Galatians 6:16).

Paul is building a careful argument. The Lord's Supper shows that believers share in Christ (1 Corinthians 10:16). Israel's altar shows that worshippers share in what is offered there (1 Corinthians 10:18). So eating at an idol's feast cannot be harmless either (1 Corinthians 10:20-21).

Behind this is a truth about worship: it is never only about the food or the outward act. Eating at a sacred table was a public act of belonging. Barnes notes that those who shared the same sacrifices were treated as one people worshipping one God. God wants all of that belonging for Himself: "Do we provoke the Lord to jealousy?" (1 Corinthians 10:22).