Note 6 at Gal. 4:26: The earthly city of Jerusalem was corrupt. It's inhabitants rejected Jesus by crucifying Him, and they, as a whole, had also rejected the gospel. But the heavenly city of God (of which the earthly Jerusalem was supposed to be symbolic) was pure and free. Those who receive salvation by faith in what Christ did for us, instead of what we do for Him through the law, are all citizens of this heavenly Jerusalem.