My Basic Bible Doctrine professor from college, Mr. McCoy has written about this. He points out one of the dangers of failing to understand covenants:
Every term/promise/command/blessing-curse is limited to the Covenant of which it was a part. The three are a unit and stand/fall together (Hebrews 7:12). When a covenant ends, like writing a new "last will and testament," it all ends and any "new" covenant will define its own parties, terms, promises and curses, and form of oath-swearing! Mixing and matching elements from different covenants has created a great deal of confusion. Many in our time want to claim for themselves OT material promises and NT forgiveness while ignoring the distinct definitions and limitations of parties and oath-swearing! A good deal of the theological confusion that exists in Christendom arises from confusion over how to handle the Biblical covenants.If you have time I would encourage you to read what Mr. McCoy wrote, Understanding Biblical Covenants, and think about how it applies to how we relate to God.