After reading Brandon Adams' JIRBS article (https://www.galaxie.com/article/jirbs07-1-03) after doing a study of Galatians 3, I determined that his basic interpretation (with similarities to David Gordon's interpretation https://www.amazon.com/Promise-Law-Faith-Covenant-Historical-Reasoning/dp/1683072081) is correct. After talking to him a bit and reading his helpful post here:
https://contrast2.wordpress.com/2017/03/18/galatians-316/ I drew up a quick note on the chapter to help me understand the interpretation as a whole. I think this to be the correct way to understand Paul's argument in Galatians 3.
And the Scripture, foreseeing that God would justify the Gentiles by faith, proclaimed the gospel beforehand to Abraham, saying, “All the nations will be blessed in you.””
= Genesis 12:3 (“And I will bless those who bless you, And the one who curses you I will curse. And in you all the families of the earth will be blessed.””), 18:18 (“since Abraham will surely become a great and mighty nation, and in him all the nations of the earth will be blessed?”), 22:18 (““In your seed all the nations of the earth shall be blessed, because you have listened to My voice.””)
So then those who are of faith are blessed with Abraham, the believer. For as many as are of the works of the Law are under a curse, for it is written, “Cursed is everyone who does not abide by all things written in the book of the law, to do them.” Now that no one is justified by the Law before God is evident, for “The righteous shall live by faith.” However, the Law is not of faith; rather, “He who does them shall live by them.” Christ redeemed us from the curse of the Law, having become a curse for us—for it is written, “Cursed is everyone who hangs on a tree”— in order that in Christ Jesus the blessing of Abraham might come to the Gentiles (as 3:8 says), so that we would receive the promise of the Spirit through faith.
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. Now the promises (plural because of the repetition of the promise of blessing the world in Gen. 12:3, 18:18, 22:18; Moo 228) were spoken to Abraham and to his seed. He does not say, “And to seeds,” (as it does in Genesis 13:8, 17:8) as referring to many, but rather to one, “And to your seed,” ("And" added to contrast Gen. 13:8 & 17:8 w/ 22:18) that is, Christ. 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. For if the inheritance is by the Law, it is no longer by the promise, but God has granted it to Abraham through the promise. Why the Law then? It was added because of trespasses, having been ordained through angels by the hand of a mediator, until the seed would come to whom the promise had been made. Now a mediator is not for one person only, whereas God is one. Is the Law then contrary to the promises of God? May it never be! For if a law had been given which was able to impart life, then righteousness would indeed be by the Law. But the Scripture has shut up everyone under sin, so that the promise by faith in Jesus Christ might be given to those who believe. But before faith came, we were held in custody under the Law, being shut up for the coming faith to be revealed. Therefore the Law has become our tutor unto Christ, so that we may be justified by faith. But now that faith has come, we are no longer under a tutor. For you are all sons of God through faith in Christ Jesus. For all of you who were baptized into Christ have clothed yourselves with Christ. There is neither Jew nor Greek, there is neither slave nor free man, there is no male and female, for you are all one in Christ Jesus. And if you belong to Christ, then you are Abraham’s seed, heirs according to the promise.
One insignificant place I disagree with Adams' interpretation is on Galatians 3:23 regarding whether it refers to the ordo or historia salutis. Adams limits it to historia. I believe it is both. Schreiner seems to do both (or at least suggest both can be done) on 247n57 as does Moo on page 241, though historia is certainly primary.
I am also very suspect of Adams' exegesis from 3:19-25 right now, but this may change. I think Galatians commentaries as a whole are noticeably lacking in quality and I hope to study the book in Greek for myself more in depth in Seminary.
