If you’re the slightest bit confused about how the New Covenant of grace in Christ is related to the Abrahamic or Mosaic covenants, I highly recommend a short book by Chad Mansbridge titled, He Qualifies You! It’s a book you can read in one sitting and it succinctly clears up any covenant confusion you might have. In the book, Mansbridge makes the clear distinction between the covenant that God made with Abraham, which was based on pedigree, and the covenant He made with Moses, which was based on performance. Then he shows how the New Covenant is based on Jesus’ pedigree and performance. Once you understand these distinctions, you’ll never be tempted to be under legalistic bondage again.
I would like to add some of my own thoughts on this.
In the third chapter of Galatians, Paul makes the painstaking argument that Abraham’s covenant with God had nothing whatsoever to do with keeping the Law. In fact, this covenant was cut 430 years before the Law. As Mansbridge also brings out in his book, there’s no requirement for Abraham to perform to any behavioral standard, nor is sin ever an issue. The only thing that matters with Abraham’s covenant was whether or not you were born from Abraham and Sarah. In other words, it was based on pedigree. You won’t find God cursing Abraham, or his offspring, for doing anything wrong because there was no law to break.
Of course, this changed with Moses when the children of Israel committed idolatry in the desert (Exod.32). They had refused to have a relationship with God directly (Exod.20:18-19), instead, wanting it vicariously through Moses. So God gave them what they wanted and strapped them with 613 meticulous rules to obey. For some crazy reason, they agreed to this arrangement, which put them under the obligation to obey every single law to the letter. The only thing that mattered with the Mosaic covenant was whether you obeyed the Law or not. In other words, this covenant was based on performance.
Now, keep in mind that while Abraham’s covenant was free from knowledge of sin or performance, humankind still had two problems. The first problem was, the only way one could be in relationship with God was biological. You must be Abraham’s direct relative. But God promised that all the ethnic nations of the earth would be blessed through Abraham.
The second problem was, all humankind was still eating from the Tree of the Knowledge of Good and Evil, still making comparisons and judgments, assessing goodness and blame from its evil fruit. And, if something weren’t done, we would eventually destroy ourselves. This is where Paul answers the question, if God’s covenant was with Abraham, then why the Law?
19 Why then was the law given? It was meant to be an intermediary agreement added after God gave the promise of the coming One! It was given to show men how guilty they are, and it remained in force until the Seed was born to fulfill the promises given to Abraham…. (Gal.3:19 TPT*)
Understand, when there was no Law, there was no sin or guilt. The only thing that mattered was your birth record, but they were still eating from the wrong “Tree.” Since the children of Israel refused the offer of a direct relationship with God (eating from the “Tree of Life”), He gave them the perfect Law with the specific purpose of showing them what fruit the Tree of the Knowledge of Good and Evil produces, which is sin and death.
What the Law does perfectly is show us how guilty we are, and how skewed our judgment really is. This is what Paul called “The Law of Sin and Death” in Romans 8:2. For the Law can only hold us in its prison until we repent and turn to Christ for deliverance (see Rom.7:24-25).
And, of course, when we turn to Christ by faith and enter into a relationship with Him, we are set free from its bondage:
2 For the “law” of the Spirit of life flowing through the anointing of Jesus has liberated us from the “law” of sin and death. (Romans 8:2 TPT*)
But, as I already mentioned, God’s promise to Abraham was also that all the ethic nations would be blessed through him. Christ fulfills this requirement by bringing all humankind to the grave with Him, so that, by faith in Christ, both the pedigree of Abraham and the performance under the Law of Moses are fulfilled. As Paul said, there’s only one “Seed” of Abraham, which is Christ, and so all who believe in Him receive what He has because God has placed us in Him!
28 And we no longer see each other in our former state—Jew or non-Jew, rich or poor, male or female—because we’re all one through our union with Jesus Christ with no distinction between us.
29 And since you’ve been united to Jesus the Messiah, you are now Abraham’s “child” and inherit all the promises of the kingdom realm! (Gal.3:28-29 TPT*)
So, now all humankind is included in Christ. We’re all invited to “eat” from the Tree of Life freely—whose “leaves bring healing to the nations” (Rev.22:1-3)—by trusting in the finished work of Christ on the cross.
This is how God fulfilled His promise to Abraham. Because Jesus brought us with Him when He rose from the dead, we’re now “born from above,” both free from the knowledge of sin (Abrahamic) and a guilty conscience (Mosaic). As Abba’s sons and daughters, we can now live according to the “life of the Spirit” (“Tree of Life”), seated in heavenly places in perfect union with Him.
And that’s the good news of Jesus Christ!