A lot of times, people look at the ten commandments and other laws that God gave in the Old Testament and they think, “This is what makes us righteous in God’s eyes. If I want to have eternal life, I have to keep these rules.”
But that way of thinking shows a misunderstanding of what the law is and isn’t. It shows a misunderstanding of what the law does and doesn’t do.
So Paul goes into detail about what exactly the law is all about. He writes,
Just as no one can set aside or add to a human covenant that has been duly established, so it is in this case. The 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,” meaning one person, who is Christ. What 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. (15-17)
The first thing that Paul says is that once a covenant has been established, one simply cannot set it aside. The word “covenant” probably holds the idea of a will. When a person makes his final will and then dies, it cannot just be set aside. Why? Because it’s a one-way “contract.” All the terms are set by one person. And its execution is based on one person’s “promise.”
That’s how God made his covenant with Abraham in Genesis 15. When he confirmed it, it wasn’t dependent on anything that Abraham did. It was solely based on God’s promise. In Genesis 15, we see God making promises to Abraham and telling him about his descendants’ future. Then God, appearing as a smoking firepot and blazing torch, walked through the pieces of some animals Abraham had cut in half. That may seem strange, but in those days, it was the common custom of two people making a covenant. After making the covenant, usually both parties would pass through the pieces, with the implicit meaning of, “If I fail to keep my end of the bargain, may I be put to death.”
But in this covenant God made with Abraham, Abraham didn’t walk through the pieces, only God did. It was a one-way contract.
And according to Paul God’s promises were made not only to Abraham, but also to his seed, that is Christ.
Paul’s interpretation of Genesis 12:7, 13:6, 15:18 and other verses which cover God’s promises to Abraham is very interesting. Obviously “seed” or “offspring” (as the word is translated in Genesis) can be plural or singular and it appears that in Genesis, God was speaking with the plural meaning in mind. But Paul seems to say that while that the blessings of the covenant would come to all of Abraham’s true children, the promise was made specifically to Christ, and that it is through him, all of Abraham’s children would be blessed.
Paul then makes clear that one thing that the law doesn’t do is make the promises of God to Abraham and us dependent on our ability to keep the law. Why? Paul tells us in verse 18,
For 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.
In other words, if the blessings of God depends on our keeping the law, then it is no longer a one-way covenant based on God’s promise. Rather, it’s dependent on our actions, and how well we can keep the law. But that’s not the basis on which God gave Abraham these promises. It was a one-way contract based on grace. And because it was a one-way contract, God cannot simply set it aside. He must keep his promises, for that is his nature. What he says he will do.
The thing to remember then is that the law was never meant to replace God’s covenant with Abraham and make the blessings God promised to Abraham and his spiritual offspring dependent on keeping God’s law.
What then was the purpose of the law? We’ll look at that tomorrow.