Gal. 3:17–18, “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.”

A woman died and left all her property to a Christian university. Or so it seemed. According to the precise terms of her will, all her “worldly goods” were “bequeathed” to a particular educational institution. The woman’s children, who lived on the other side of the country, were surprised to discover that they had been left out of their mother’s estate. “Surprised” is hardly the word for it. They were outraged that the college had “taken advantage” of their mother in this way.

The children decided to contest the will in a court of law. They tried to claim that their mother’s bequest applied only to personal effects and not to real estate. But in the end they lost their case and, with it, any chance of gaining an inheritance. There was nothing they could do to change the terms of the will. As far as the law was concerned, the matter had been settled when the old woman died.

The Permanence of the Covenant

This is the kind of legal situation Paul has in mind in Galatians 3:15. Throughout this chapter he has been proving that justification and the Holy Spirit come by faith and not by works. First he argued from experience—the experience the Galatians had when they received the Holy Spirit (Gal. 3:1–5). Next he argued from Scripture—the biblical record about Abraham, the man of faith (Gal. 3:6–14). But when it comes to making a theological point, it always helps to have a good illustration, so next Paul takes “a human example” (Gal. 3:15). His illustration comes from the world of jurisprudence. According to standard legal practice, “with a man-made covenant, no one annuls it or adds to it once it has been ratified” (Gal. 3:15). The covenant is permanent.

By “covenant,” Paul does not have in mind a legal contract for a business transaction. He refers instead to a covenant for an inheritance, what today might be called a “last will and testament.” Whereas the Greek word diathēkē usually means “covenant,” it can also mean “testament,” and in this passage the latter is the better translation. A will is not a contract. It does not set terms that various parties are obligated to fulfill. Instead, it simply declares what one party intends to do. A last will and testament is a legal arrangement in which one party bestows his or her estate on someone else. It is a grant rather than a bargain.

The kind of human covenant Paul has in mind is also irrevocable. Once it is signed, sealed, and delivered, it cannot be changed. There is no way to set it aside or add to it. It cannot be abrogated or annulled. It cannot be amended or adjusted. It is legally binding exactly as it stands.

There is some debate as to which legal system Paul had in mind when he spoke about this human covenant. Roman law was like English law. Roman covenants could be annulled or added to. A man (usually property owners were men) could tear up his old will and write a new one at any time. Or he could add a codicil to change the terms of his original will. Among the Romans, it was only when the man died that his testament could no longer be altered. If Paul was thinking in terms of Roman law, this is what he meant by “ratified.” A last will and testament was permanently settled at death. American jurisprudence works the same way. Once an estate has gone through probate, it cannot be redivided.

Greek law was slightly different from Roman law. According to the Greeks, a will could not be repealed or revoked. It could not even be modified. Once it had been properly registered and deposited at the public-record office, a Greek testament could never be altered. This practice would fit Paul’s point exactly: once the covenant was made, it was irrevocable.

But perhaps the apostle was thinking in terms of Jewish inheritance law. The Jews had a special procedure for making an irrevocable testament prior to death. This was called mattenat bari, and there is a good example in the story Jesus told about the prodigal son: “There was a man who had two sons. And the younger of them said to his father, ‘Father, give me the share of property that is coming to me’” (Luke 15:11–12). The younger son asked for his inheritance before his father died. In other words, he was asking for mattenat bari, an irrevocable testament that could be neither added to nor annulled.

It is not certain which legal system is intended in Galatians 3, but it hardly matters. In any legal system, there comes a time when a testament is settled once and for all, either by death or by some official action. After that point, nothing can be done to change the terms in any way.

If this is true at the human level, it is all the more true when it comes to the covenant God established through Abraham: “Just as no one can set aside a human covenant that has been duly established, so it is in this case” (Gal. 3:15 NIV). Paul’s argument is from the lesser to the greater. What holds true in a human court has even greater force in the courtroom of Almighty God.

The analogy of a last will and testament is a good one because it has several points of comparison with the Abrahamic covenant. Consider the conditions of that arrangement, which the Scripture repeatedly calls a “covenant” (Gen. 15:18; 17:2; etc.). And since it was a covenant, Paul was able to compare it to the covenants of his day. As far as covenants go, what God proposed to Abraham was more like a testament. It was not a contract set up between relative equals. On the contrary, it contained a long list of things God promised to grant as his legacy to Abraham.

The Abrahamic covenant was properly established. In those days, legal agreements were not based on a handshake or a piece of paper. Instead, they were sealed in blood by a covenant ceremony:

“[God] said to him, “Bring me a heifer three years old, a female goat three years old, a ram three years old, a turtledove, and a young pigeon.” And he brought him all these, cut them in half, and laid each half over against the other.…

When the sun had gone down and it was dark, behold, a smoking fire pot and a flaming torch passed between these pieces. On that day the Lord made a covenant with Abram.” (Gen. 15:9–10, 17–18)

The animals were sacrificed and God passed between them, thus validating his covenant in a legally binding way.

Paul’s point is that what God covenanted to do for Abraham that night would remain in force forever: “Paul regards the promise to Abraham as a divinely ratified settlement or covenant and argues from its considerable priority to the law that its provisions cannot be made null and void by the later introduction of the law.” One cannot adjust the terms of a human testament, much less a divine one. Therefore, once God duly established his covenant, it could never be annulled or amended. It was permanent.

The Party to the Covenant

What does all this have to do with the Galatians, or with us? Paul answers this question by identifying the party to the covenant: “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” (Gal. 3:16).

Here again Paul proves to be a careful student of the Old Testament. God repeated his promises to Abraham on several occasions. Often he made his promise to Abraham’s offspring as well as to Abraham himself: “Then the Lord appeared to Abram and said, ‘To your offspring I will give this land’ ” (Gen. 12:7); “all the land that you see I will give to you and to your offspring forever” (Gen. 13:15); “To your offspring I will give this land” (Gen. 24:7). In Galatians, what Paul wishes to emphasize about the word “offspring” is that it occurs in the singular. The Bible says “offspring,” not “offsprings.”

By resting his case on the ending of a noun, the apostle teaches something important about the authority of the Bible. How could he make such a precise point from the Hebrew text of the Old Testament unless he believed that the Bible is God’s Word written? Even though he did not use these precise words, Paul obviously believed that the Bible is infallible and inerrant from beginning to end.

Paul and the other inspired authors of the New Testament paid careful attention to the grammar and context of the Old Testament passages they quoted, and this is a perfect example. Paul knew full well that “offspring” was a collective noun. In fact, he uses the word that way several times, including later in this very chapter (Gal. 3:29). He also knew that the offspring God promised to Abraham would be as numerous as the sand and the stars. But Paul wanted to explain that God’s covenant promises referred to someone in particular. In Galatians 3:16 he is not so much making an argument based on Old Testament grammar as he is explaining what the Old Testament really means. The promise of the offspring referred first of all to Abraham’s son Isaac. Ultimately it referred to all of God’s children, but especially to God’s Son, Jesus Christ.

Jesus Christ is the true offspring. He is the party to the covenant that God made with Abraham. The covenant was all about Jesus Christ. It looked forward to his coming. This is why Paul could claim, just a few verses earlier, that the Scripture “preached the gospel beforehand to Abraham” (Gal. 3:8). What God promised to Abraham was the good news about Jesus Christ, for it is in him that all nations on earth are blessed.

This shows how God’s covenant with Abraham has something to do with us. As Paul explained earlier in the chapter, we do not have to be biologically related to Abraham to claim his inheritance. All we need is faith in Jesus Christ. The true sons of Abraham are not identified biologically, but Christologically. The covenant promise was really for Christ, and when we belong to Christ, the promise belongs to us.

Once we understand that God’s promise to Abraham is a promise to Christ, then the fact that the word “offspring” is a collective noun makes perfect sense. A collective noun can refer either to a single individual, or to a group of individuals, or to both. So it is with the offspring of Abraham. The promise refers first of all to a single individual, Jesus Christ. But it also refers to a collection of individuals, namely, everyone who belongs to Christ. The party to the covenant is Christ and all who are in him. God gave the promise to Abraham. The promise was Christ. Since we are in Christ, the promise is for us. In the words of the Puritan William Perkins, “The promises made to Abraham are first made to Christ, and then in Christ to all that believe in him.”

Here we are reminded again of the doctrine of union with Christ, which is so central to Galatians and to Paul’s theology in general. The Christian is in Christ. We participate in him. By faith we are incorporated into him. We have covenant solidarity with him. We are so united to Christ that what is his becomes ours. To quote again from Perkins, “The right way to obtain any blessing of God, is first to receive the promise, and in the promise Christ:and Christ being ours; in him, and from him, we shall receive all things necessary.”

It is almost as if there is only one party to the covenant: Jesus Christ. But this is exactly what the Galatians were in danger of forgetting. By trusting in the works of the law, they were dividing the church along racial lines: Jews on one side, Gentiles on the other. They were not united in Christ. Paul used the promise to the offspring, therefore, to remind them that God’s eternal plan is for one family in one Christ. By the time he gets to the end of chapter 3, this will be the climax of his argument: “in Christ Jesus you are all sons of God through faith.… And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise” (Gal. 3:26, 29).

The Promise of the Covenant

“Promise” is a key word in Galatians 3, appearing eight times in the last fifteen verses. What Paul says about the promise of the covenant is that it comes before the law.

Perhaps this is a good place to review the apostle’s argument: Verse 15 described the permanence of the covenant, which was established once and for all when God gave it to Abraham. Verse 16 identified the party to the covenant. God’s promise to Abraham was also made to Christ, and to everyone who is in him. Next Paul clarifies the promise of the covenant, saying, “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” (Gal. 3:17).

The promise and the law are two separate, though complementary, arrangements. They operate on entirely different principles: faith and works. The promise is about what God will do, while the law is about what we must do. The difference between the promise and the law is evident from the vocabulary God used when he first gave them. When he made the promise to Abraham, God said, “I will, I will, I will.” But in the law of Moses God said, “Thou shalt, thou shalt, thou shalt.”

The law and the promise operate in entirely different ways, a difference John Stott explains as follows: “The promise sets forth a religion of God—God’s plan, God’s grace, God’s initiative. But the law sets forth a religion of man—man’s duty, man’s works, man’s responsibility. The promise (standing for the grace of God) had only to be believed. But the law (standing for the works of men) had to be obeyed.” And when we say that the promise had to be believed, we do not mean a belief that is bare assent, but a firm and trusting grasp of God and all that he has promised in Christ.

These two different principles—promise and law—are not on equal terms. One has the priority. Within God’s covenant of grace, it is the promise that takes precedence over the law. The law is secondary within the history of redemption, not primary. The law principle is subordinate to the promise principle.

For one thing, the promise came first in time. God gave Abraham the promise long before he gave Moses the law. In keeping with the length of Israel’s captivity in Egypt (Ex. 12:40–41), Paul says that the law came almost half a millennium later, 430 years after the promise. Some might argue that the law therefore superseded the promise. Or that the law supplemented the promise, which is what the Judaizers were trying to teach the Galatians. They wanted to add works to faith as the basis of their standing before God. In other words, they were trying to make the law an addendum to the promise.

This is exactly why Paul introduced his legal illustration. God’s promise to Abraham was an irrevocable covenant. It had the same status that a will has after it has gone through probate. There was no way it could be invalidated. The law could not replace the promise. It could not even supplement the promise. Once God made his covenant, it could never be annulled or added to.

This means that the gospel has more to do with Abraham than it does with Moses. The Judaizers were fond of Moses, which is why they tried to introduce a legalistic version of Christianity. They said that the law was necessary to make the promise complete. It took works to finish what faith had started. By the time the Judaizers were finished with them, the Galatians needed to be reintroduced to the doctrine of justification by faith alone. For as far as justification is concerned, the law is just a Moses-come-lately. It did not change the terms of God’s promise, as if God had signed a contract with Abraham and then changed his mind by adding some fine print for Moses.

Besides, if the law had been necessary for salvation, it would have come too late to do Abraham any good! When God gave Moses the law, Abraham had been dead for centuries. Fortunately, he had been justified by faith long before the law of Moses was even introduced. Abraham’s salvation was not based on anything Abraham did. The covenant did not establish any legal requirements that he had to satisfy. It all came free, the way an inheritance always does. God’s covenant with Abraham came with no strings attached—no ifs, ands, or buts. The covenant was entirely a matter of promise, received by faith.

Heirs of the Promise

If the covenant was based on promise, then it could not come through the law. This is the conclusion of Paul’s argument: “For if the inheritance comes by the law, it no longer comes by promise; but God gave it to Abraham by a promise” (Gal. 3:18). This is the way inheritance law always operates. A beneficiary receives an inheritance on the basis of a binding legal promise. Therefore, if God has promised an inheritance, it must come by way of promise, and not by works of the law.

This brings us back to the point Paul has been trying to make all through this letter, the point recovering Pharisees keep needing to hear: God deals with us according to his promise, and not according to our performance. We are justified by faith only and not by works. If God’s covenant was established by faith and not by works of the law, then the covenantal relationship God has with the Galatians through Christ is also by faith and not by works of the law. It was the same for the Galatians as it was for Abraham, and it is also the same for us: we are justified by grace through faith.

To see why this is so, it helps to remember how promises work. It is impossible to earn a promise. The only way to receive a promise is to trust in it. If a wealthy benefactor promises to give me a house in Huntington Beach, California there is nothing I can do to fulfill the promise. The only thing I can do is to trust him to keep his promise (or not, as the case may be). I may decide it is prudent to secure my own housing, just in case my would-be benefactor fails to make good on his promise. But I cannot fulfill his promise to me on his behalf.

So it is with the promises of God’s covenant. Only God can fulfill them. Therefore, when he promises us salvation, it follows that we cannot earn it for ourselves: “For the promise to Abraham and his offspring that he would be heir of the world did not come through the law but through the righteousness of faith. For if it is the adherents of the law who are to be the heirs, faith is null and the promise is void” (Rom. 4:13–14).

This brings us to a very practical conclusion: God deals with us according to his promises, not according to our works. Everything God has to offer comes through a promise. And so, writes John Stott, “every sinner who trusts in Christ crucified for salvation, quite apart from any merit or good works, receives the blessing of eternal life and thus inherits the promise of God made to Abraham.” As it was for Abraham, so it is for everyone who is in Christ.

Salvation in Christ does not rest on a law that we inevitably break; it rests on a promise that God cannot break. God has promised forgiveness of sins through the death and resurrection of Jesus Christ. He has promised eternal life to everyone who comes to Christ in faith. God will not—indeed, he cannot—go back on his promise. His covenant is an irrevocable will and testament. It stands firm forever.

Salvation in Christ is not a commercial transaction. My relationship with God is not based on my ability to make a deal or strike a bargain. The Christian life is not a quid pro quo, so that if I do what God wants, then God will do what I want. God simply does not operate this way. Instead, my relationship with God is based entirely on believing his gracious promise.

What God promises is an inheritance, and it is the right of whoever bestows an inheritance to set his own terms. God can do what he wants with his spiritual blessings. His legacy includes forgiveness of sins, fellowship with Christ in the Spirit, and the free gift of eternal life. What God has decided to do with his legacy is to give it clear away. As the Scripture says, “God gave it to Abraham by a promise” (Gal. 3:18). The word “gave” appears in the perfect tense to show a past action with present results. It means that salvation is a gift given once and for all and then kept forever.

Since salvation is a matter of God’s free grace, we do not have to work to obtain it. No one ever works for an inheritance! It is a gift, not a paycheck. We receive our inheritance from God the same way Abraham received it: by faith. We simply believe that God will make good on his promise to save us through the death and resurrection of Jesus Christ. And then, of course, we act on our faith, living like the true heirs of God that we have become through his covenant in Christ.

A good illustration of what this means in practical terms comes from a professor on a university campus in the Far East. One of his students came to him in despair and confided that he was a practicing homosexual. “I feel like a slave,” the young man lamented. The professor responded with the loving truth. “You are a slave,” he said, and then he began to teach him about gaining freedom from sin through faith in Jesus Christ.

This was so attractive to the student that he wanted to become a Christian himself. But there was one thing that held him back: the thought that he was not good enough for God. How could God forgive him for everything he had done? So he said to his professor, “First I must become a Christian like you. Then God will love me.”

The professor responded by saying, “I’m not a Christian like me, either. I’m no better than you are, except for the love and power of God. He loves you now as you are.” This is the grace of God, that he does not deal with us on the basis of our performance, but on the basis of his promise. No matter what we have done, our sins are covered by the covenant righteousness of Christ. And now that we are in Christ, our standing before God does not fluctuate with the inconsistency of our daily obedience. On the basis of the promise that he made before the law, God loves us with an unconditional love.