Galatians 3:15-18

V15-18 – ¹⁵Brothers, let me take an example from everyday life. Just as no one can set aside or add to a human covenant that has been duly established, so it is in this case. ¹⁶The promises were spoken to Abraham and to his seed. The Scripture does not say ‘and to seeds,’ meaning many people, but ‘and to your seed’ [Genesis 12:7; 13:15; 24:7], meaning one person, who is Christ. ¹⁷What I mean is this: The law, introduced 430 years later, does not set aside the covenant previously established by God and thus do away with the promise. ¹⁸For if the inheritance depends on the law, then it no longer depends on a promise; but God in His grace gave it to Abraham through a promise.

Paul has made it clear that Abraham was justified by faith and not by works of law, through the Spirit and not by the flesh. But one objection to this conceded truth might be that, since the law was given after the time of Abraham, the law may actually override the previous means of being declared righteous by God. Thus, to point out in this section that the law later given to Moses did not nullify the covenant promise God made to Abraham and his seed, Paul uses “an example from everyday life,” that of a permanently established grant or declaration (opposed to an agreement or bargain), perhaps akin to a last will and testament, through which an inheritance is left to a beneficiary. And that’s the comparison Paul makes to God’s covenant promise. And that’s the picture we see in Genesis when God ratified His covenant with Abraham. Now Paul knows that the word “seed” or “offspring” may be collective even in the singular, like our more common word, “family,” but his point is clear (v29; Romans 4:18), that Christ is the offspring to whom we must be united to receive the inherited promise made to Abraham.

In v17, Paul tries to clarify his remarks by saying that just as “no one can set aside or add to a human covenant that has been duly established, so it is in this case” (v15). It’s an argument from the lesser to the greater; if a human contract is considered binding (rendered effectual), how much more binding is a divine contract? The law, though given much later than the promise, “does not set aside” or “do away with” the covenant promise. (Paul uses 430 years, from Exodus 12:40, and this number from the Septuagint includes the stay of the patriarchs in Canaan; That he uses 430 does not mean that he used the Septuagint; Kim Riddlebarger acknowledges that “Paul here is using the standard rabbinic reckoning of the years counted between Moses and Abraham.”) Despite the fact that a long time passed between the promise and the law, works of law do not override grace through faith, according to the promise (Romans 4:14-16). Vincent Cheung says, “The inheritance was given to Abraham by promise – by God’s sovereign declaration of what He would perform – and ratified in blood. And as we have seen, the promised blessing is applied through faith to those whom God has chosen to believe. The law, which came after, does not affect this, whether we are referring to the promised inheritance or the means by which it is applied (v18). Therefore, the principle of justification by faith is preserved despite the formal institution of the law.”