In Paul’s day, traveling speakers carried letters of commendation emphasizing personal qualifications and achievement in order to gain welcome and hospitality. Such letters would be much like a résumé or reference letter today.
It is interesting to think of people being a sort of reference letter for our Christian life. Paul points to the church at Corinth as his letter of commendation, as clear, tangible evidence that he is doing the work of the Lord. I wonder: who would our letters of commendation be? What people would we point to as bearing clear evidence of a growing relationship with Christ as a result of our having invested heavily in their spiritual development?
It is also interesting that the Corinthian church is not perfect. There are still problems. But Paul does not let that keep him from seeing the church in Corinth as a true church, and as such evidence of the Spirit’s working. The degrees to which we reflect God’s glory may very (vs 18), but they are a reflection still.
Yet another point of interest (there are so many!) is that Paul sees this letter of recommendation as being written on his own heart! I take this to be another way of Paul saying that he constantly carries the people he cares for in his heart. Whatever their response to him may be, he is deeply affected by them.
And I have found this to be true in ministry as well. Whatever the response of the people God calls us to love is to us, and indeed to the Gospel we preach, we are still bound to them. They are engraved upon our hearts, and that is as it should be. And so again we might ask, who is engraved upon your heart?
Finally, Paul also takes the idea of a letter of commendation and uses it as a metaphor for the Christian life in general. People do “read” our lives. Our lives do proclaim what is really in our hearts, which is often very different than our words. May ours be lives that are letters “of Christ”; that is, lives that proclaim first and foremost that Jesus lives in our hearts, and that Jesus is Lord!