2 Corinthians 3:7 - Matthew Poole's English Annotations on the Holy Bible

The apostle is manifestly comparing the ministry of the gospel with the ministry of the law, and showing the excellency of the former above the latter. In the former verse he had called the law, the letter; and the gospel, in opposition to it, he had called, the spirit: here he calleth the ministration of the law, the ministration of death; because it only showed man his duty, or things to be done, but gave no strength or help by which he should do them; only cursing man, but showing him no way by which he might escape that curse: so it did kill men, and led them to eternal death and condemnation, without showing them any means of life and salvation. He also undervalueth the law, in comparison with the gospel, as being only written and engraven in stones; whereas (as he had said before) the gospel is written in the fleshy tables of men's hearts. Yet (saith he) the ministration of the law (which was indeed but the ministration of death) was glorious: there was a great deal of the glory and majesty of God attended the giving of the law, of which we read, Exodus 19:1-25. So that the children of Israel could not stedfastly behold the face of Moses for the glory of his countenance: of this we read, Exodus 34:29,30: When Aaron and all the children of Israel saw Moses, behold, the skin of his face shone; and they were afraid to come nigh him. So as it was glorious to be but a minister of the law, that is, of the revelation of the will of God, as to man's duty, which glory (saith the apostle) was to be done away: Moses's face did not always so shine, neither was the glory of his ministration to abide always, but to cease by the coming in of the new covenant.