New glory

 But if the ministry of death, written and engraved on stones, was glorious, so that the children of Israel could not look steadily at the face of Moses because of the glory of his countenance, which glory was passing away, how will the ministry of the Spirit not be more glorious? For if the ministry of condemnation had glory, the ministry of righteousness exceeds much more in glory. For even what was made glorious had no glory in this respect, because of the glory that excels. For if what is passing away was glorious, what remains is much more glorious. - 2 Corinthians 3:7-11

The Law was not a waste. Indeed it was glorious. So glorious in fact that when Moses went up to receive the Law and came back the people could not even look at his face for the glory. But the glory that hid Moses' face did not last forever. It eventually faded. Like that the ministry of condemnation under the law had a measure of glory, but it fell short. In God's divine plan all it could do is to point out to men where they failed. It was glorious in accomplishing that, for without the knowledge of sin there could be no effective gospel message. 

The glorious system of the Law has been surpassed. In its place is something that dims its glory. The angels announced it when they said 'glory to God in the highest, and on earth peace, goodwill toward men.' The glory of the gospel of Christ is so bright that it makes the glory of the law seem like no glory at all. 

What passed was glorious. It was a marvelous schoolmaster to bring us to Christ. But what remains is the glorious gospel and we have the glorious privilege of taking part in the glorious ministry of sharing it with all those around us.