In order to understand Galatians 3:15-18, we need to know Paul’s flow of thought beginning from verse 1.
First, in verses 1-5 Paul argued from every Christian’s own conversion experience and sanctification. That is, we received the Spirit by faith and God sustains the Spirit through faith and we will be perfected by the Spirit through faith. Then second in verses 6-9, Paul supported the main theses by arguing from Scriptures, that we, like Abraham was, will receive the promised inheritance by faith and third in verses 10-14 that those who are of faith and not those who are of the works of the law are the true children and heirs of Abraham by quoting from Old Testament. Now from Galatians 3:15-4:11 he will argue from a salvation-historical perspective or what we call in theology as redemptive history.
Redemptive history simply means the unfolding in history of God’s one plan of salvation through a series of covenants in order to redeem a people for Himself. So a basic understanding of redemptive history is necessary in order for us to get a handle of Paul’s argument as to why the law is of different category from faith, as he mentioned earlier from verse 12.(For further studies visit: Biblical Covenants)
The main point of verses 15-18 is that the Mosaic Law cannot nullify the previously ratified Abrahamic Covenant, therefore the promise stands valid. In other words, the inheritance is received via the promise given to Abraham, and not by means of the law given to Moses.
This section serves as an answer to an objection that quite possibly raised by the Judaizers against Paul’s position. They may have said: “Paul, you’re mistaken in saying that the means of receiving God’s promises is by faith alone apart from works of the law. Because clearly, God thought it necessary to add the law after His promise to Abraham, in order to make clear that it is by works of the law that we will receive the inheritance. Otherwise the law would have serve no purpose.” Paul then gave his answer in verses 15-18 what the purpose of the law is not. It is not meant to amend or annul the covenant. Also notice what he said in verse 19, “Why then the law?” This seems to suggest that Paul anticipates their false deduction: “If what you’re saying is true, then you render the law as useless.” But then Paul answered what’s the real purpose of the law in verse 19 and its temporary nature(this is for another time) . Therefore this confirms that in verses 15-18 Paul is demolishing one argument as to why the law was given, namely the one suggested by the Judaizers.
Now Verse 15 and verses 17-18 must be treated as one unit separated by a break in Paul’s line of thinking in verse 16. The segue is not that far from the main subject though, since it merely explains to whom the promise was given. But having said that, we will deal with verse 16 separately because it makes a different point as it stands by itself.
Now Paul begins in verse 15 with an analogy from everyday human life. Even human beings consider covenants to be unbreakable. Once they are ratified, no one can annul them, add to them or alter them. This could be strange to us since we can change and annul or render void our wills and covenants(ex. Marriage covenant) today. But we must understand that during their time, at least some wills and covenants were seen as irrevocable or immutable. There are several examples of covenants between human beings in the OT that were considered to be irrevocable (Gen 21:22-32; 26:26–31; 31:44–45; 1 Sam 18:3; 20:8; 22:8; 23:18; 2 Sam 3:12).
Then Paul resumes the application of the analogy in verse 17. Thus we can paraphrase what’s being said here this way: “15 just as with human covenants no one annuls it or adds to it once it has been ratified, 17 even more so the law cannot annul or alter the covenant with Abraham that was previously ratified by God.” Paul therefore is arguing from the lesser to the greater. Even human covenants, with all its limitations and failures, we treat it as irrevocable, how much more should we treat as irrevocable God’s perfect covenant.
Now let’s look at how Paul applied the analogy in verse 15 to the Abrahamic covenant and the Mosaic covenant in verse 17.
The temporal aspect between the promise and law is in the forefront of Paul’s argument here. That’s why I began with the discussion of redemptive history because it is very important for us to know where we fall under God’s covenants and which came first. We are said to be, on this side of the cross as under the New Covenant. But here we are talking about two covenants prior to the New Covenant and Paul’s argument here relies heavily on which of these two covenants came first, not just logically but also chronologically. The Mosaic covenant came 430 years after the Abrahamic covenant was given and for Paul, it cannot invalidate or supersede the provisions of the Abrahamic covenant.
Now according to Thomas Schreiner: “The rabbis did not typically read the Scriptures in terms of its overall story line but mined the OT for truths wherever they were found. It is likely that Paul’s opponents maintained that the Mosaic covenant supplemented and “defined” the Abrahamic [covenant] . Paul argues, however, that the chronology in which the story unfolds is fundamental for reading Scripture rightly. The Abrahamic covenant and its promises preceded the Mosaic covenant (and the giving of the law) by 430 years. The covenant with Abraham, then, takes precedence, and the law functions as a subordinate and interim covenant that cannot invalidate the terms of the Abrahamic covenant.”
Schreiner’s point is that the very error that’s being propagated by the Judaizers was the same error the rabbis committed. Namely, the failure to read the scriptures in light of the overall storyline as it unfolds in history.
But Paul’s argument here will only work if it can be shown that the Mosaic covenant has nothing to do with the Abrahamic covenant. That is, the covenant given to Israel through Moses is essentially different from the covenant given to Abraham by God. The two must be of a different nature or a different plane. If the Mosaic covenant merely restates the same covenant that was given to Abraham then the argument based on chronology would be irrelevant. So there must be a disjunction between the two. So Paul further supports verse 17 with verse 18. He says; “For if the inheritance comes by the law, it no longer comes by promise” Notice that what can be said of the law and promise can be said also of works and faith. For if inheritance comes by works of the law, it no longer comes by faith in the promise. With law and works, you’ll receive what is due, because it is conditional. But with the promise and faith, you’ll receive grace and mercy, because it is unconditional. The two covenants therefore are of different categories. They are incompatible but not in the sense of they are contradictory.
So what’s left then in this section of the argument is the support Paul gave in the last part of verse 18; “but God gave it to Abraham by a promise.” That’s the same thing as saying Abraham and his descendants will not receive the inheritance as due to their law keeping but they will receive the inheritance because of believing the promise. But can Old Testament scripture support his claim that God gave a covenant that is a promise based covenant and not a law based covenant?
When God gave the covenant to Abraham, He made an oath by himself and for Himself. This covenant is unconditional. God made promises to Abraham that required nothing of Abraham. Instead, God is unwavering with His commitment to fulfill this covenant that He made a sort of ceremonial oath while Abram was asleep in Genesis 15:8-21.
This therefore clearly demonstrates for us that the Abrahamic covenant is a covenant of promise to be believed in and not a law covenant to be worked on. The oath God gave was conditioned not with what Abraham must do and can do but what God can do and his power and faithfulness to fulfill His promises. So in essence, to go back to the law is more than just going back in time opposite to where we are in redemptive history, but it’s going back to offer God some help in order to fulfill His promises and that is blasphemy.
So we come now to verse 16. But before we begin with its exposition, let’s ask first why preface the main argument of verses 17-18 with a discussion about the interpretation of the word “offspring” in verse 16? He could’ve just gone straight to verse 17 and apply his analogy from verse 15. We can only guess what’s in the mind of Paul here. However, I can’t help but see that he wants his readers to understand this two covenants in light of their fulfillment, namely the New covenant. We are unlike Abraham who believed the promise and hoped for its fulfillment. We on the other hand, believe in light of the fulfillment of God’s promise as we look back to the cross. We are also unlike Moses and those who lived under the Mosaic covenant as they believe what the shadows and types entail when they present their sacrifices of lambs for temporal forgiveness of sins. We however, believe the Christ, the one who cast those shadows, who died as the perfect lamb of God for the forgiveness of sins and securing for us eternal life when He rose from the grave. Paul is saying then that when we think of the promise, think of the offspring. Do not divorce the discussion of God’s promises and law from its fulfillment.
Now the question that might be lingering in your minds at this very moment is; “Can Paul really argue this way? Isn’t it that the word ‘offspring’ even without ‘s’ is many by definition because it’s a collective noun? So how can he argue based on its singularity? ”
The answer is yes! Paul can argue that way and yes the word “offspring” is a collective noun that by its very definition refers to many individuals. But wait, before you say that Paul was good only with history, yet with grammar he fails, pause lest you blaspheme the Holy Spirit who superintend the writing of this letter. We believe in the inerrancy and infallibility of Scriptures. The whole of Scriptures.
So what’s happening here then?
First we must understand that Paul’s not a dummy. He knew that offspring in its singular form can be used to refer to many, just like in Romans 9:7. So this is not a mistake but a conscious decision from Paul to argue this way.
Thomas Schreiner says the same thing: “Paul finds significance in the singular form of the word “offspring” (σπέρματι) and distinguishes it sharply from the plural “offsprings” (σπέρμασιν). The distinction drawn is surprising since “offspring” is a collective singular. Nor is Paul ignorant of this fact, for he uses the singular “offspring” (σπέρμα) as a collective just a few verses later (3:29).”
But did he depart from exegesis and turned into allegory? No because there’s actually a precedence of the usage of the word “offspring” in the Old Testament which refers only to a single individual. In Genesis 4:25, Moses used the collective noun “offspring” to refer only to Seth; “God has appointed for me another offspring.” That’s the same usage even in the Spetuagint. Or in Genesis 21:12; the “offspring” refers to Isaac only.
Lastly, Paul’s used of the collective noun makes perfect sense because Christ himself represent all those who are united to him through faith. And that’s the point of Galatians 3:6-7 and Galatians 3:9.
So what’s the relationship then of the “offspring” in verse 16 and a “promise” in verse 18? Clearly the promise in verse 18 is not the inheritance(though this too was referred to as the promises) because the promise here is the means by which one receives the inheritance. I think the offspring in verse 16 explains the promise in verse 18. The promise is that a seed of Abraham will become the means by which we can receive the promised inheritance. On the other hand, the inheritance is salvation(the receiving the Holy Spirit, justification, adoption, sanctification and glorification ) by being united with Abraham’s Seed through faith.
Many professing Christians today thinks that theology is a kind of hindrance to growth. Deep and long study of the word of God is impractical. For them, the most practical way to grow is to eat quick. Let’s just eat soundbites, and theology from memes that I can immediately apply to my ever busy life. But the too technical, with elaborate exegesis and extremely theological study is bad for my diet. I don’t see how the relationship of two covenants apply to my life now. Or how knowing the singularity of a noun as significant affect how I deal and relate with my wife, my children, my neighbours or my co workers and my bosses.
That’s how all of us rationalise our laziness to study the word of God deeply, and we think we’re being pragmatic that way. We’re being practical. But I’ll say this, when it comes to spiritual growth, there’s no more pragmatic way than to feast in the word of God, or than to dive deeply into the wealth of God’s word and be hooked with all the arguments and intricacies of theology. It will teach you to become humble and know that we’re just scraping the surface of God’s wisdom. It will cause you to cry with tears of joy because of knowing how deep God’s love for us and sometimes with tears of broken-heartedness towards the sinfulness of our sins as it was revealed in Scriptures. Deep and long study of God’s word is the breeding ground for patience and self control. It will teach you to be patient and learn not to just read through a text. It will also lead you to control your tongue before giving any dogmatic statements. We may not see immediately how the grammar of a text shapes not only our theology but also how we live our lives, it nevertheless is working. Don’t be immature and impatient, thinking that you can take the shortcut to growth. Just like with eating, we digest properly the nutrients of the food we eat when we chew slowly. That is, relishing every bite. So you want to be practical? Then grow deep in theology.