For an introduction to this series, click here.
This chapter begins with a defense of Paul's ministry, including his apostleship, which is a major theme of the later portion of this book:
"Are we beginning to commend ourselves again? Or do we need, as some do, letters of recommendation to you, or from you? You yourselves are our letter of recommendation, written on our hearts, to be known and read by all." (3:1-2)
Paul took on immediately those who questioned Paul's apostleship and standing in the church. Paul was saying his position in the church spoke for itself. He did not need letters from other preachers or other kind of thing to bolster his reputation. His reputation was based on the results of his ministry.
Paul makes a jump from a discussion of his own place in the church to some of the clearest teaching on the differences between the old and new covenants: "Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God, who has made us competent to be ministers of a new covenant, not of the letter but of the Spirit. For the letter kills, but the Spirit gives life. Now if the ministry of death, carved in letters on stone, came with such glory that the Israelites could not gaze at Moses' face because of its glory, which was being brought to an end, will not the ministry of the Spirit have even more glory? For if there was glory in the ministry of condemnation, the ministry of righteousness must far exceed it in glory. Indeed, in this case, what once had glory has come to have no glory at all, because of the glory that surpasses it. For if what was being brought to an end came with glory, much more will what is permanent have glory." (3:5-11)
It is interesting that Paul calls Moses' law the "ministry of death," because in other places Paul is insistent that the Law was holy and was God's plan for that time. I think in this case he is using a slight bit of hyperbole to demonstrate the difference between the old and new covenants and the danger of trying to return to the old covenant.
It is important to note that Paul describes the "ministry of death" as being "carved in letters on stone." Paul is talking about the 10 Commandments here. Yes, even that is done away with in Christ. Not that we can go out and kill people or wantonly commit adultery. Jesus and the Apostles are clear that such things are sin. But there are at least 2 of the 10 that most Christians don't even worry about breaking any more: keep the Sabbath day holy and no graven images. We recognize that Saturday is not holy any more, and we don't have a problem with coin money, pictures and other things that clearly violate the graven images prohibition. If it's fine to break 2 of them, why do we feel obligated by the other 8? We need to be more consistent in the way we apply Scripture to our lives.
The last section of this chapter is one of my favorite passage in all the Bible: "Since we have such a hope, we are very bold, not like Moses, who would put a veil over his face so that the Israelites might not gaze at the outcome of what was being brought to an end. But their minds were hardened. For to this day, when they read the old covenant, that same veil remains unlifted, because only through Christ is it taken away. Yes, to this day whenever Moses is read a veil lies over their hearts. But when one turns to the Lord, the veil is removed. Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. And we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image from one degree of glory to another. For this comes from the Lord who is the Spirit." (3:12-18, ESV)
First of all, Paul talks about the fact that most Jews, even to this day, are blinded to the truth of Christ. It is interesting that Paul says that only through Christ is the veil taken away. This means that one cannot truly understand the Old Testament the way God intended without the knowledge of Christ.
And of course the last verse is one of the most profound verses in all of the Bible. God is at work in every Christian's life, even when the person is not always aware of it. He is at work bringing us closer and closer to the image of the glory of the Lord. Of course we can grieve the Spirit and slow down the process, but that does not mean that the Lord is not at work each and every day in our lives. That fact brings confidence and assurance that God is not going to leave us alone and hasn't forgotten about us. He will bring about His plan, and the more we submit to that plan the easier the process becomes.