Paul had spent some time in Corinth. it must have been heartbreaking to have to take them to task about their failure to mature as Christians:
1 Corinthians 3:1-3 Dear brothers and sisters, when I was with you I couldn’t talk to you as I would to spiritual people. I had to talk as though you belonged to this world or as though you were infants in Christ. I had to feed you with milk, not with solid food, because you weren’t ready for anything stronger. And you still aren’t ready, for you are still controlled by your sinful nature.
What an accusation! Paul had already taken the Galatians to task about making a choice about what they lived for.
But what did Paul say to the Corinthians, who were still controlled by their sinful nature, when he was with them?
1 Corinthians 2:1-4 … I didn’t use lofty words and impressive wisdom to tell you God’s secret plan. For I decided that while I was with you I would forget everything except Jesus Christ, the one who was crucified. I came to you in weakness—timid and trembling. And my message and my preaching were very plain. Rather than using clever and persuasive speeches, I relied only on the power of the Holy Spirit.
But to mature believers, Paul was prepared to teach more in depth:
1 Corinthians 2:6, 13 Yet when I am among mature believers, I do speak with words of wisdom, but not the kind of wisdom that belongs to this world or to the rulers of this world, who are soon forgotten. … Instead, we speak words given to us by the Spirit, using the Spirit’s words to explain spiritual truths.