Galatians 3:15-18, Promise, Not Law

If I promised you in a contract that I would cover all your mortgage payments every month, but then later established rules for how you treated your home and refused to pay when you didn’t keep the rules, you would rightfully have a case to take to court. Paul has been defending the gospel he preached

• by evidence that it was revealed to him by God,
• by the evidence of how this was the gospel that transformed the Galatians’ lives,
• and by the evidence of Scripture.

He has shown that the gospel that saved Abraham was justification (being declared righteous by God) by faith, not works. Now he argues from the nature of God’s covenant or contract with Abraham that the promise cannot be overthrown by the Law.

15 Brothers and sisters, even in the human realm, when a covenant is ratified, no one can nullify it or add to it. 16 Now the promises were spoken to Abraham and to his seed. It does not say, “And to his seeds,” as if spoken to many, but as to one, “And to your seed,” which is Christ. 17 What I’m saying is, the law which came 430 years after the covenant was previously ratified by God, does not nullify so as to abolish the promise. 18 For if the inheritance is based on the Law, it is no longer based on the promise. But God bestowed the inheritance to Abraham based on the promise. (Galatians 3:15-18)

It is possible that the false teachers argued with the Galatians that because the Law of Moses came later it was God’s way of salvation. But Paul turns that argument on its head. The covenant God made with Abraham could not be abrogated by the Law. Even human covenants are not subject to nullification or addition, how much more God’s covenant.

But who are the recipients of this covenant? Can the Gentile converts claim it? Yes, because the covenant was made to Abraham and to his “seed.” We understand that the singular word seed can be refer to a plurality, being a collective noun. And the Old Testament understands it this way. But critical to understanding the Old Testament is the notion corporate solidarity, how the individual can stand for the group and vice versa. So, for example, when Yahweh tells Joshua that Israel, His people, have sinned (Joshua 7:11), He is referring to the sin of Achan in stealing items from Jericho that were considered under the ban and to be destroyed. He holds the nation accountable for the sin of one man.

Paul understands this principle and knows that Abraham’s seed ultimately refers to Messiah.

Paul realizes that he must first prove that the Abrahamic covenant applies to the Christian era. He does this by means of a special form of interpretation (then quite common), in which he sees in “seed” (which could be either singular or plural) a “corporate solidarity” in Christ. That is, Christ is the “seed” about whom God made promises, and all those who are “in Christ” are also the “seed” (v. 29). (NIV Application Commentary)

Hence, the Gentile believers in Galatia are the recipients of this promise because they are in Christ. Therefore, the Galatians are heirs of the promise. The inheritance in the Old Testament is the land, but as Meyer says, “in its N.T. sense, the conception of the κληρονομία [inheritance] is elevated to the idea of its Messianic fulfilment (Matthew 5:5), so that the kingdom of the Messiah and the whole of its fulness of salvation and glory are understood thereby.”

Consequently, the Law does not nullify the covenant of the promise. In fact, if the Galatians switch to keeping the Law as the basis for gaining the inheritance, they will lose it. Such a dependence on the Law contradicts the promise God established as the basis for getting the inheritance, the kingdom. Paul’s gospel wins!

So why was the Law introduced? Paul explains that biblically next.