A. Andrew Das, Paul and the Stories of Israel: Grand Thematic Narratives in Galatians (Minneapolis, MN: Fortress Press, 2016), 123:
Second Temple Jewish authors frequently praised Abraham for his faithfulness in circumcising his household, obeying the as-yet-unwritten Law of Moses, and, in that climactic moment, nearly sacrificing the child of promise. The Jews also praised Isaac for his willingness to be sacrificed. Paul steers clear of any reference to Abraham’s faithfulness or his obedience in the near-sacrifice of Isaac as he emphasizes, instead, the irrevocability of the oath God made with Abraham that day. Paul also ignores Abraham’s son Isaac and the physical people descended from him. Instead he claims the single Seed of Abraham is Jesus Christ, and the enjoyment of the full rights of Abrahamic sonship is only “in” Christ, whether for Jew or non-Jew. Paul keeps the focus on how God has been faithful to the promises of old rather than on the faithfulness of Abraham or on a people of merely physical or fleshly descent.
The Amateur Exegete 