Had the letter ended with chapter 2, the Corinthians could have thought of themselves as Paul’s spiritual allies. Have they not accepted his message, thereby proving that they too are spiritual (1 Corinthians 2:6–16)?

This makes Paul’s words in this verse all the more startling. He does not go as far as to say that the Corinthians do not have the Spirit, and he still addresses them as brothers. Yet he rebukes them for not behaving like spiritual people. Ever since he had preached the gospel to them, he had found them to be infants in Christ, rather than mature (see 1 Corinthians 2:6).

Paul has in mind the year and a half that he had spent in Corinth, teaching the Word of God to the first believers (who were mostly of Jewish background; see Acts 18:1–11). Even at that time, the Corinthian believers had displayed many characteristics of people of the flesh. Perhaps this helps to explain why Paul had only baptized a few of them (1 Corinthians 1:14–16).

As in Romans 8:1–11 and Galatians 5:16–26, Paul uses the term flesh to refer to the fallen human nature, that is, to man without the Spirit.