In 1 Corinthians Paul is writing to a church out of order and out of sync with God. He greets them knowing that God is faithful to complete the work He has started in them, but there are issues that need to be addressed. There are times when rebuke and correction are necessary. Sin left unchallenged will continue to grow. Paul's first and primary concern is division — not sexual immorality, drunkenness, or other sins that had arisen in the church. Division starts in the heart and results from walking in the flesh and relying on ourselves rather than being Spirit-filled and Spirit-lead. Holy unity comes when we fully surrender to Christ, doing all things for His glory and put others above ourselves.