Bird's-eye view
In this tightly-argued section, the Apostle Paul brings a legal case, drawn from everyday life, to bear on the monumental question of how a man is made right with God. Having established that Abraham was justified by faith, and that all who believe are sons of Abraham, Paul now anticipates the great objection from the Judaizers: "What about the Law of Moses?" Paul’s answer is devastatingly simple. He argues that the promise God made to Abraham was like a ratified, legally-binding will. Once a will is in force, you cannot come along centuries later and add new conditions that effectively nullify the original inheritance. The Law, given 430 years after the promise, cannot annul the promise. Furthermore, the promise was made to Abraham and his singular "seed," which Paul identifies as Christ. The inheritance of salvation is therefore a gift, received by promise, not a wage, earned by law. The two systems are mutually exclusive, and God's original covenant of promise has absolute priority.
This is covenant theology in action. Paul is showing that God's plan of salvation by grace through faith is not a New Testament invention. It was there from the beginning, in the covenant with Abraham. The Mosaic Law had a purpose, which Paul will explain later, but its purpose was never to provide an alternative way of salvation. God does not have a Plan A (promise) and a Plan B (law). He has one plan, centered on the promise, fulfilled in the Seed, who is Christ.
Outline
- 1. The Unalterable Covenant of Promise (Gal 3:15-18)
- a. The Analogy from Human Law: A Ratified Will (Gal 3:15)
- b. The Specificity of the Divine Promise: To the One Seed (Gal 3:16)
- c. The Chronological Priority: Promise Before Law (Gal 3:17)
- d. The Logical Incompatibility: Inheritance by Promise, Not Law (Gal 3:18)
Context In Galatians
Paul is in the thick of his central argument against the Judaizers. He has just demonstrated from the Old Testament itself (Genesis 15:6) that the father of the faithful, Abraham, was justified by faith, not by works of the law. He has also established that all who are of faith are the true sons of Abraham (Gal 3:7) and that the gospel was preached beforehand to Abraham (Gal 3:8). This section, verses 15-18, is a crucial pivot. Paul now defends the integrity of this original gospel promise against the claims of the Mosaic Law. He is building an airtight case that the coming of the law did not and could not change the terms of salvation. This argument is essential for showing the Galatians that their attempt to be justified by circumcision and law-keeping is not a step forward into mature Christianity, but a step backward, away from the covenant of promise and into bondage.
Key Issues
- The Binding Nature of a Covenant
- The Relationship of the Abrahamic and Mosaic Covenants
- The Singular "Seed" as a Messianic Prophecy
- The Mutual Exclusivity of Law and Promise as a Basis for Justification
- The Primacy of God's Promise in Redemptive History
God's Ironclad Will
The Judaizers were attempting to perform some celestial legal maneuvering. They wanted to take God's covenant of promise with Abraham and attach a massive, law-shaped codicil to it. They were treating the Mosaic Law as an amendment that fundamentally changed the terms of the original agreement. Paul, with the skill of a master lawyer, steps forward to demonstrate that this is legally, logically, and theologically impossible. God's covenants are not flimsy suggestions that can be altered on a whim. The promise God made to Abraham was a solemn, ratified testament, and God does not go back on His word. Paul is about to show that the entire system of the Judaizers is built on a foundational misunderstanding of how God works in history.
Verse by Verse Commentary
15 Brothers, I speak in human terms: even though it is only a man’s covenant, yet when it has been ratified, no one sets it aside or adds conditions to it.
Paul begins with an appeal to common sense, drawing an analogy from everyday legal practice. He says, "I speak in human terms," meaning, "Let's just think about how things work down here on earth." Even with a purely human contract or will, a man's covenant, once it is legally ratified, it's fixed. You can't just ignore it (set it aside) or tack on new stipulations (add conditions). The deal is the deal. This is a principle everyone understood. A last will and testament, once validated, is binding. Paul is establishing a baseline of legal stability that his opponents cannot deny. If this is true for the fallible agreements of men, how much more true must it be for a covenant solemnly ratified by the unchanging God?
16 Now the promises were spoken to Abraham and to his seed. He does not say, “And to seeds,” as referring to many, but rather to one, “And TO YOUR SEED,” that is, Christ.
Having established the principle of an unalterable covenant, Paul now examines the specific terms of God's covenant with Abraham. The promises were made to two parties: Abraham and his seed. And here Paul makes a point that has caused no end of consternation for modern commentators, but which is the linchpin of his argument. He points out the singular form of the word "seed" (sperma in Greek, translating the Hebrew zera). The promise was not made to "seeds" as though it were a scattered inheritance among many disparate groups. It was made to one "seed." Paul, writing under the inspiration of the Holy Spirit, identifies this singular seed as Christ. This is not a cheap grammatical trick. It is a profound theological insight. The promise to Abraham was always a Messianic promise. It finds its ultimate fulfillment, its focal point, and its very substance in the person of Jesus Christ. All who are heirs of the promise are heirs only because they are united to that one Seed. We are not a multitude of individual seeds; we are made part of the one Seed, who is Christ.
17 And what I am saying is this: the Law, which came 430 years later, does not invalidate a covenant previously ratified by God, so as to abolish the promise.
Here Paul applies the legal principle from verse 15 to the divine reality. He puts the two covenants on a timeline. First, you have the covenant of promise, "previously ratified by God." Then, 430 years later (counting from the patriarchs' entry into Egypt to the Exodus), the Law arrives at Mount Sinai. Paul's logic is unassailable. This later arrival, the Law, cannot reach back in time and "invalidate" the prior, already-in-force covenant. To do so would be to "abolish the promise," making God's original word null and void. If the Judaizers are right, then God gave Abraham a promise that had a 430-year expiration date, after which a whole new system of earning the inheritance would be instituted. Paul says this is unthinkable. It would make God an unreliable covenant partner. The promise stands. The law does not, and cannot, cancel it.
18 For if the inheritance is by law, it is no longer by promise, but God has granted it to Abraham through promise.
Paul concludes this section with a statement of mutual exclusivity. You can have the inheritance in one of two ways, but not both. It is either by law or it is by promise. If it is by law, then it is a wage that is earned through performance. If it is by promise, it is a gift that is received through faith. The two principles are fundamentally opposed. You cannot have a gift that you also have to earn. To introduce law as the basis for the inheritance is to destroy the very nature of promise. And Paul delivers the final blow: the undisputed fact is that God has granted the inheritance to Abraham as a gift, through a promise. The Greek word for "granted" here is kecharistai, which is rooted in the word for grace (charis). The inheritance was, from the very beginning, an act of sheer grace. The case is closed. The foundation of salvation is God's gracious promise, not man's dutiful performance.
Application
The argument Paul makes here is not some dusty theological artifact. It is the foundation of our Christian assurance and the bulwark against every form of legalism that plagues the church. The core message is this: your relationship with God is based on a promise He made, not on a performance you render. God's covenant with us in Christ is an ironclad, ratified will. He has promised to save all who are in the "one seed," Jesus Christ.
This means we can have rest. We are not on probation. We are not constantly having to check if we have fulfilled the latest conditions that some teacher has tried to add to the gospel. Any time you hear a message that sounds like "Jesus plus...", Jesus plus your quiet time, Jesus plus your political activism, Jesus plus your dietary habits, Jesus plus your particular worship style, you are hearing the Galatian heresy in modern dress. It is an attempt to add conditions to a will that God has already ratified in the blood of His Son.
Our standing before God does not depend on our ability to keep the law, but on God's ability to keep His promise. And He has kept it perfectly in Christ. The inheritance is ours not because we are good, but because He is gracious. It is not earned by works, but received by faith. We must therefore be vigilant to defend this truth. We must rest in the finished work of the one Seed, and refuse every temptation to add our own flimsy works to the unshakeable foundation of God's eternal promise.