The passage
      v1. It is always difficult, when defending our character, not to end up being charged with self-praise. Up to this point in his letter, Paul has spent time defending his integrity and so now asks a rhetorical question, "are we beginning to commend ourselves again?" He has obviously faced this criticism, so he seeks to expose it. As Goudge puts it, "self-defense is almost impossible without self-commendation. Paul's opponents at Corinth made the former necessary, and then blamed him for the latter."
      He then asks another rhetorical question. Do the Corinthians actually require Paul to supply commendatory letters (from the Jerusalem church?) to support his apostleship? One hopes not, but obviously their behavior implies that they do.
      v2. Of course, Paul can actually produce an evidence of his authority. "The Corinthian church does not make Paul an apostle, and his apostleship does not depend on them, but their existence is a visible sign of his apostleship", C.K. Barrett. The existence of the Christian fellowship at Corinth is a commendatory letter of Paul's apostleship for all believers to witness, and is one which has a special place in his deepest emotions.
      v3. Paul now extends the image of a commendatory letter. The Corinthian church itself is such a letter from Christ to the world. The existence of the church demonstrates the reality of the gospel - of God's purpose to gather a people to himself in Christ. This in turn validates Paul's apostolic ministry as a bearer of the gospel. Going on in v3b, Paul makes another subtle change. "What is written is now no longer a commendatory letter, but the gospel which stands over against the law, and is written in men's hearts through the Spirit", Lietzmann. So, ultimately the gospel and its effects are his authorization. And more than this, they replace the "tablets of stone" (Ezek.10:19, 36:26 - the tables of the law) as the witness to the new covenant.
      v4. Paul's confidence rests in the gospel and its effects.
      v5. Paul goes on to categorically state that he does not regard himself as responsible for the effects of the gospel. The capacity of the apostolic team to understand and proclaim the gospel and to reap its harvest, comes from God.
      v6. Only God can take mere mortals and empower them as ministers (in this context, proclaimers of the gospel); "ministers", says Paul, of "a new covenant." The covenant idea springs from v3 where Paul speaks of the gospel written on "human hearts." The prophet Jeremiah, in his new covenant prophecy, speaks of the day when the law will be written in the heart rather than on stone, 31:31-34. The new covenant, or new agreement, between God and mankind is in the gospel message. The agreement is the promise of a new relationship with God through faith in Christ. To hear and believe is to have the reality of this relationship inscribed in our hearts, in our inner beings, through the Holy Spirit. It is this life-giving message ("of the Spirit") which Paul and his apostolic team proclaim. They do not proclaim a message "of the letter", ie. a legalistic Christianity based on a misunderstanding of the Law and its function.

Ministers of the new covenant
      In our passage for study we see the apostle Paul defending his apostolic authority. In doing so, he gives us an insight into ministry. Although he is defining the authenticity of his own ministry, what he says applies to all Christian ministers, and that means all of us. The Bible teaches "the priesthood of all believers". That is, we are all ministers of the gospel, it's just that we all minister differently.
      Paul claims for himself, and his apostolic team, the title of "ministers of the new covenant", communicators of God's new agreement with mankind. The agreement is the gospel, it is the free offer of inclusion in God's new community of friends for all who ask Jesus for membership. Our task, as ministers of the new covenant, is to make this truth a reality in our lives, that of our family and friends, fellow believers, and the world at large. We do this by applying our resources of time, talent and tinkle to the business of nurture and evangelism, and so we serve as ministers of the new covenant and fulfill our Lord's command to go into all the world and proclaim the gospel.
      Paul goes on to make three observations about ministry which should encourage us in this "raison detre", this reason for our day-to-day existence:
        i] Our ministry is commended by the Lord and needs no commendation by others;
        ii] We may be confident of the effectiveness of our ministry for such is Christ's work and not ours;
        iii] The competence of our ministry is of Christ's making, not ours.

v2
      eggegammenh (eggrafw) perf. pas. part. "written" - having been written / inscribed. "A letter inscribed on your hearts", Bruce.
      hJmwn "[written on] our [hearts]" - "our" is well attested, but some manuscripts have "your" and this is a more sensible reading. Paul's ministry among them is well known to them and this is his commendation.
      anaginwskomenh (anaginwskw) pres. pas. part. "read" - being read. cf. 1Cor.9:2. "You are the seal of my apostleship in the Lord", in the sense of Paul's evidence to the world.
      uJpo pantwn anqrwpwn "by everyone" - by all men. The evidence of the gospel, ministered by Paul and at work in the Corinthians, can be accessed by anyone who looks on.

v3
      faneroumenoi (fanerow) oJti pres. pass. part. "You show that" - being manifested that. "Since you are manifested", but possibly, "because it is manifest that....." Heiring suggests the word is middle and therefore, the Corinthians are a "manifestment." The Corinthian church serves as a communication from Christ to the world.
      diakonhqeisa (diakonew) uJf hJmwn "ministered by us" - having been served by us. Given that the Corinthian church is here described as "a letter", the sense is probably "delivered" or "supplied" by Paul's ministry team. "You are like a letter written by Christ and delivered by us", CEV.
      melani (melaV) adj. "ink" - black, ink. Ink can we washed away, but the Spirit's inscription (the gospel), evident in the lives of the Corinthians, is permanent.
      plaxin (ax axoV) "tablets" - A writing tablet usually moulded out of clay
      sarkinaiV adj. "human [hearts]" - fleshly .... as opposed to something written on stone. The evidence of the gospel written in the lives of the Corinthians, replaces the evidence of the of the old covenant written on stone (the Law / ten commandments).

v4
      pepoiqhsin (iV ewV) "confidence" - confidence. Literally, "we have such confidence." "It is in full reliance upon God through Christ", Barclay.
      proV ton qeon "before God" - Barrett suggests "in God", in that Paul would not be suggesting that he is relying on his own worth. His confidence is not self-confidence. So, his confidence before God is in God.

v5
      iJkanoi adj. "competent" - sufficient, competent, capable, qualified, able, worthy. "There is nothing in us that allows us to claim that we are capable of doing this work", TEV.
      iJkanothV (hV htoV) "competence" - sufficiency, competence, capability. The word is sometimes used of God, the All Sufficient One. Dodd suggests the word has covenantal links. Paul's missionary effort find its source and authority in God and thus is adequate for the task.
      ti "anything" - everything to do with the process of the gospel at work in the lives of the Corinthians which serves as a witness to the world