Just out is an article on Galatians 4 and Romans 9-11. Much has been written about Paul’s use of the analogy/allegory between Hagar/son of slavery and Jerusalem above/son of freedom. It will be interesting to see what Wolter has to say.
Michael Wolter, “Das Israelproblem nach Gal 4,21-31 und Röm 9-11.” Zeitschrift für Theologie und Kirche. 107:1 (2010): 1-30.