In his recent devotional from God Pause, Pastor Wayne Peterson of St. Barnabas Lutheran Church in Plymouth, Minnesota explained it best:
2 Corinthians 3:12-4:2
In his letters to the Corinthians, Romans and Galatians, Paul in some places refers to the law given to Moses in less than positive terms. This passage is one of those places.
It is important to not pluck these passages out of their larger context and have them stand alone, for doing so gives an incomplete view of Paul’s understanding of the law. For Paul, the law is God’s good gift, but it was never intended to be God’s final word. God’s final word is, and must always be, Christ. Here, Paul uses the allegory of Moses and the veil (the allegory actually starts in v. 7) to make the point that the proper role of the law is seen only in the light of Christ. It is Christ (the Spirit of the Lord) who takes away the veil, who allows us to experience the freedom of the gospel.
Lord Jesus, you have revealed to us the freedom we have in the gospel. Help me hold in proper tension the freedom to do as I please with the responsibility I have to serve my neighbor. Amen.
2 Corinthians 3:12-4:2 (NRSV)
12 Since, then, we have such a hope, we act with great boldness, 13 not like Moses, who put a veil over his face to keep the people of Israel from gazing at the end of the glory that was being set aside. 14 But their minds were hardened. Indeed, to this very day, when they hear the reading of the old covenant, that same veil is still there, since only in Christ is it set aside. 15 Indeed, to this very day whenever Moses is read, a veil lies over their minds; 16 but when one turns to the Lord, the veil is removed.
17 Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. 18 And all of us, with unveiled faces, seeing the glory of the Lord as though reflected in a mirror, are being transformed into the same image from one degree of glory to another; for this comes from the Lord, the Spirit.
4:1 Therefore, since it is by God’s mercy that we are engaged in this ministry, we do not lose heart. 2 We have renounced the shameful things that one hides; we refuse to practice cunning or to falsify God’s word; but by the open statement of the truth we commend ourselves to the conscience of everyone in the sight of God.