Imprisoning Everything under Sin
Having shown through Scripture that the law brings not salvation but curse, and that Christ Jesus himself became that curse for us, Paul now anticipates the question, “Why then did God give to us the law in the first place?” This is a very legitimate question and one he must answer in the face of those who are troubling the church by insisting on the keeping of the law through circumcision and ceremonies.
Paul has already alluded to Abraham, the father and beginning of the Israelites. God made a promise to Abraham and his “offspring,” Paul making much over the fact that the word is singular, though it certainly has a corporate meaning, and Paul himself used it in a corporate sense in Romans 4:18. Regardless, Paul’s point is that the offspring (in both the singular and corporate senses) to whom the promise was made was Christ himself, through whom those who believe receive the promises. Christ is the intermediary between believers and the Father, the Father being one with His Son. But Paul’s main point here is that this promise which was given to Abraham and his offspring long before the law was given to Moses by some 430 years cannot be annulled by that law. That promise constitutes a sacred covenant and testament of the Father to His Son and those who believe in His Son and is thus inviolable.
So the question rises again, “Why then the law?” Paul answers, “It was added for transgressions.” What does that mean? Let us look to what Paul wrote in his letter to the Romans, “Through the law comes knowledge of sin” (3:20), and “That sin might be shown to be sin, and through the commandment might become sinful beyond measure” (7:13; also see notes in ESV Study Bible, 2250). Paul goes on to argue that had there been a law that gave life then righteousness would have come by the law. But this cannot be the case with fallen human beings whose sinful nature cannot abide the law. The problem is not with the law; the problem is with us. So God does us a favor: He imprisons everyone under sin. But how is this a favor to us? So that “the promise by faith in Jesus Christ might be given to those who believe.”
So you see, the promise came first; the law only came to show us how much we needed and still need the promise. So don’t cling to the law; cling to the promise which was fulfilled in our Lord’s coming and his passion and resurrection on our behalf. Cling, I say, to the Lord.