What does 1 Corinthians 10:18 mean?

Paul is building his case for why the Corinthians should not knowingly eat food offered to an idol. He has just described how taking part in the practice of Christian communion, consuming together representations of Christ's body and blood, makes believers active participants in Christ's body and blood.

Now Paul refers to the Israelites who ate food sacrificed on an altar. This can be read in one of two ways. Paul may be talking about the times that the Old Testament sacrificial system allowed the priests or the people to eat food that had been offered to God (Leviticus 7:11–21). In that case, Paul is showing how this caused them to be connected to God and to each other.

The other option is that Paul is referring to what he wrote earlier in this chapter about the Israelites in the wilderness who worshiped false idols (1 Corinthians 10:7). In that case, they offered sacrifices to the golden calf and then ate those sacrifices together (Exodus 32:5–6). Paul's point in this verse, then, would be that those Israelites had become attached in some significant way to that altar by eating the food sacrificed on it. They were participants with that altar in the same way that Christians are participants in Christ through the practice of communion.

Next, Paul will show that those who knowingly eat food offered to idols risk becoming participants with those false idols and the real demons behind them.