I’ve been working through Paul’s letters with my ordinands in several different courses, and just now it hit me that scholars typically treat Paul’s interpretation of Abraham as a retrospective rationalisation in light of his satori concerning the Torah and ’justification’. That is, they start from the premise that Paul’s breakthrough concerned the importance of considerations other than law-adherence relative to the Gentiles’ inclusion; he saw the ‘insufficiency’ of the Law for making Gentiles righteous, indeed for making anybody righteous, and then sorted out the implications for this with respect to Abraham. ‘Look! It turns out that God blessed him before he was circumcised!’ This emerges as a knock-down rationale for including the Gentiles as far as Paul is concerned, and he moves on exploring his Law-free gospel in other directions.
But I wonder whether that may get it wrong way around — that Paul may have noticed, one day, that God reckoned Abram righteous before circumcision, and that that entailed the insight that Gentiles can be justified apart from works of the Law. This would fit better with my inclination to read Paul as the theologian par excellence of difference-in-harmony, and only secondarily as a theologian according to whom ‘reckoned’ justification comes to eclipse Law-adherent behaviour as the basis for inclusion in the People of God.
I am not a Pauline specialist (IANAPS), so I’m probably missing somebody who thought this before me, but I’m ready to argue it provisionally as the best explanation for the trajectories of Paul’s thought. Until, that is, someone who knows the literature better sets me straight.