We do well to remember that what we have in a letter like 2 Corinthians is not just a personal letter to a church. It WAS that, but it was more than that. It is the inspired Word of God. It was meant from the very outset, by God’s design, to be a teaching instrument for the whole church and for the rest of time.

Why does a Holy Spirit-inspired letter that includes personal explanations for changes in travel plans, and a personal defense of his character and the faithfulness of his ministry?

There are several good reasons.