Galatians 4 Extra - Abraham's Sons
I hope you've been enjoying our time in Galatians 4 these last few Sundays. There was a lot to get through in the first part of the chapter, and I didn't feel I could apply the idea of "don't be enslaved again" in sufficient detail and unpack the technicalities vv21-31 in the same sermon. I'm still learning...!
Nevertheless vv21-31 are no less part of God's word and have some massive things to say, particularly in clarifying the relationship between New Testament believers and the Story of Israel in the Old Testament.
In summary Paul makes a quite momentous statement: the true people of God, the beneficiaries of the promise to Abraham are not the inhabitants of geographical Jerusalem, his Jewish Contemporaries. Rather they are the members of the Jerusalem that is above - a citizenship attained only through faith in Christ Jesus. He makes his point by a stunning allegory - that of Isaac and Ishmael, Sarah and Hagar. The Jews, of course, naturally saw themselves as the descendants of the promise, children of Sarah with Isaac as their spiritual forefather. The extraordinary suggestion made by Paul is that his Christ-denying Jewish contemporaries shared in the fate not of Isaac, but of Ishmael, whilst the believers, including the Gentile believers could all count themselves the descendants of Isaac by faith, and therefore see themselves as possessing the full freedom of the children of God. It is hard to overemphasise how radical a departure from his Jewish roots these words of Paul represent.
Now, that's all well and good, you may say, but what about the business of the barren woman and so forth quoted from Is 54:1. Far be it from me to give you a half baked explanation when I can point you to Professor Doug Moo author of the Baker Exegetical commentary on Galatians who gave a series of talks at Oak Hill on the book recently.
The relevant talk is also embedded here. Zoom along to 47 minutes in for Moo's excellent explanation of Gal 4:21-31.