To give a human example, brothers: even with a man-made covenant, no one annuls it or adds to it once it has been ratified. Now the promises were made to Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, “And to your offspring,” who is Christ. This is what I mean: the law, which came 430 years afterward, does not annul a covenant previously ratified by God, so as to make the promise void. For if the inheritance comes by the law, it no longer comes by promise; but God gave it to Abraham by a promise. – Galatians 3:15-18 ESV
As a former Pharisee, Paul had a scholarly understanding of the Old Testament. But it was after his conversion, when he had received the indwelling Holy Spirit, that Paul truly began to understand that the Old Testament was a foreshadowing of the coming Messiah, Jesus Christ. Post-conversion, his comprehension of the Scriptures was both magnified and clarified. Familiar passages took on a whole new meaning when he was able to view them through the lens of the gospel. In the case of Genesis 13:15 and 17:8, where Moses records God’s covenant to Abraham, Paul exegetes these all-too-familiar passages by revealing that through them, God had been promising the coming of Christ. He was the “seed” or “offspring” through whom all the nations would be blessed. God’s promise to Abraham would ultimately be fulfilled through Jesus. But what is Paul’s point in bringing this new understanding of God’s promise to light? He was attempting to answer the argument that the Mosaic law, which came after the giving of God had made His covenant with Abraham, somehow superseded or supplanted it.
On the contrary, Paul argues, God had made a binding covenant with Abraham and his “offspring.” That God-ordained covenant could not be nullified or broken. It was a unilateral covenant, made by God and could only be annulled by God. But Paul stresses that at no point did God revoke or replace the covenant, even when He had given Moses the law some 430 years later. In fact, Paul points out, the inheritance tied to the promise of God could be received only through the promise of God. It was not accessible any other way, especially not through the keeping of the law. And the inheritance of which Paul speaks is tied directly to the idea of justification by faith. This was the crux of the problem taking place among the Galatian believers. They were being told that their justification was tied to the keeping of the law, most specifically to God’s command regarding circumcision. In other words, they were being sold a bill of goods that promised them a right standing before God through law-keeping and self-effort, not faith in Christ alone.
Paul wrote to the Colossian believers:
May you be strengthened with all power, according to his glorious might, for all endurance and patience with joy, giving thanks to the Father, who has qualified you to share in the inheritance of the saints in light. He has delivered us from the domain of darkness and transferred us to the kingdom of his beloved Son, in whom we have redemption, the forgiveness of sins. – Colossians 1:11-14 ESV
He prayed for the Ephesians…
that the God of our Lord Jesus Christ, the Father of glory, may give you the Spirit of wisdom and of revelation in the knowledge of him, having the eyes of your hearts enlightened, that you may know what is the hope to which he has called you, what are the riches of his glorious inheritance in the saints… – Ephesians 1:17-18 ESV
For Paul, the promise of God made to Abraham and fulfilled in Christ, was all about the wonderful reality of a restored relationship with Him, available to both Jews and Gentiles. And this incredible gift was only available through faith in the finished work of Jesus Christ, His Son. It could not be attained through self-effort. Paul went on to tell the Ephesian believers that he wanted them to understand…
…what is the immeasurable greatness of his power toward us who believe, according to the working of his great might that he worked in Christ when he raised him from the dead and seated him at his right hand in the heavenly places… – Ephesians 1:19-20 ESV
Our salvation, justification, sanctification and glorification are all tied to the work of Christ on our behalf. Our righteousness comes from Christ. Our right standing before God is as a result of His shed blood. Our future inheritance is tied His sacrificial death on the cross. All that we are and all that we hope to have is based on the finished work of Christ. And for that we have much to be grateful.
None of this negates the necessity of obedience to God in our lives. Faith and works are not an either/or proposition. For Paul, it was a matter of order or priority. Faith comes first. But true saving faith is always followed by good works. Works are the fruit of faith. Works cannot provide justification, but they can certainly prove it. As Paul told the believers in Ephesus, “we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them” (Ephesians 2:10 ESV). Paul speaks of the inheritance made possible through the promise. That is directly tied to our justification with God. We have been made right with Him and enjoy a restored relationship with Him. Not only that, we are His sons and daughters, His heirs. Paul wrote to the believers in Rome: “This means that it is not the children of the flesh who are the children of God, but the children of the promise are counted as offspring” (Romans 9:8 ESV). Just a few verses later in his letter to the Galatian believers, Paul reminds them, “if you are Christ’s, then you are Abraham’s offspring, heirs according to promise” (Galatians 3:29 ESV).
Our privileged position as children and heirs of God is a direct result of the promise of God. And it was made available to us by the Son of God. When we place our faith in His saving work done on our behalf, rather than on our own attempts to earn God’s favor, we are made right with God and stand before Him as righteous. Not because of anything we have done, but because of what Christ has done for us.