What does 1 Corinthians 14:38 mean?

The Corinthians have been given a set of very specific instructions about what should and should not happen in worship services. Paul insists they should receive his teaching about these things as commands from the Lord. As an apostle of Jesus, Paul officially represented Christ's words and will to other believers. Paul wrote in the previous verse that any spiritual people—those "in the Spirit"—and anyone with the gift of prophecy should acknowledge this to be true (1 Corinthians 2:14).

Now he adds that any among them who do not recognize these commands as coming from Christ will also not be recognized. The implication is that those who oppose Paul in these areas, those who disregard his teaching, will themselves be disregarded or ignored by God. In other words, those who reject the clear teaching of God about these things risk being revealed as not belonging to God. This is not an accusation Paul makes lightly (Galatians 1:8–9), or without cause.

Those who believe God and are known by Him will receive His instructions, including those delivered by Paul, and will act on them.