Another contrast between the two covenants concerns the medium God used to carry them to His people. He employed stone tablets for the Old Covenant but His Holy Spirit for the New Covenant. These vehicles represent the nature of each covenant: hard and unbending compared to personal and friendly. [source][source][source]
Another contrast is the relative glory of the ministries that marked the economies that the covenants created. "Glory" is a key word in this section of the epistle. It occurs19 times in chapters1-8 , and15 of these references appear in chapters3,4. "Glory" appears as a noun and a verb10 times in 2 Corinthians 3:7-11. Both covenants involved ministry to God that resulted in glory for God. However the glory of the New Covenant far surpasses the glory of the Old Covenant. Here Paul began to think about the glory that appeared on Moses" face when he descended from Mt. Sinai after he had communed with God for40 days and nights ( Exodus 34:29-35). The glory (i.e, the manifest evidence of God"s presence) was so strong when Moses reentered the camp that the Israelites could not look at him for very long. The evidence of God"s presence was very strong during the economy when a covenant leading to death governed God"s people. How much stronger, Paul argued, will be the manifestation of God"s glory in an age when His life-giving Spirit inhabits His people?[source]