After sending the tearful letter with Titus, Paul planned to meet with Titus in Troas for a report. When this meeting did not happen, Paul grew concerned the Corinthian church was upset with him. Titus was a Greek co-worker of Paul mentioned in several letters, including a short letter written to him while he was working with churches in Crete. Titus is a long-time co-worker, since Paul had taken Titus to Jerusalem before Acts 15 to show that God was working among the Gentiles (Gal 2:3).
Paul said in 2 Corinthians 1:8-11 he was in “deadly peril in Asia,” probably indicating a time of suffering in Ephesus. This may have included an arrest although it is not mentioned directly in Acts, Philippians may imply Paul was arrested and placed in custody in Ephesus. In 1 Corinthians 15:32 he refers to “fighting the wild beasts in Ephesus,” which could refer to literal animals, or vicious opponents who behaved like animals. Paul listed many afflictions described in 2 Corinthians 4:8-9, and perhaps even his “thorn in the flesh” (12:7) is in mind here.
“Fightings without and fears within” implies he had considerable internal fear concerning this persecution or even the success of his mission in Ephesus and later in Troas. Why world Paul be afraid? “It probably seemed to Paul that from the human point of view his whole future as apostle to the Gentiles was related to the Corinthians’ reaction to his assertion of authority in the letter delivered by Titus. And now the non-arrival of Titus tended to confirm his worst fears.” (Garland, 351, citing Harris).
Paul’s missed connection with Titus may have aroused fears for Titus’s own safety, since many thing could have happened to him when he traveled to Troas. This tends to be human nature, if someone is very late arriving we tend to create a worst case scenario and worry about that (perhaps unlikely) possibility.
Another aspect of this fear may have been a result of the attacks he faced in Corinth. What if his opponents convinced the church to reject Paul as an apostle and no longer listen to him as the Lord’s appointed representative? The very fact he is being challenged by someone in the congregation was humiliating to him personally, he has lost honor and been humbled by his challengers in the church.
Titus was not sent to the church to attack them or forcibly get them back in line with Paul’s orders. He was sent to deal with a serious spiritual challenge, there was real sin in the church that needed to be confronted and excised from the congregation. Paul is not like a medieval bishop who imposes an unwelcome order on a fearful congregation!
Paul describes his time of uncertainty as “mourning,” but the news from Titus was a cause for rejoicing. The church was not upset from the tearful letter, they were in fact comforted, Titus was comforted by their response, and finally Paul himself was comforted by the news from the church. This church was on grief over the letter, but the grief is “contrition over their past behavior or a sense of loss from Paul’s decision to continue to stay clear of Corinth” (Garland, 353).
In summary, the “tearful letter” was a necessary thing, but now that they have responded positively, Paul apologizes for the pain he caused the church. Paul was confident the church world respond to his tearful letter, even if there was come fear it might cause them pain. But not all grief and pain is bad, in fact godly grief produces a great deal of positive virtues. If Paul had upset them with his strong challenge, that pain is a positive benefit if they are reconciled to him.