Where did Paul get his anthropology?

Our Pauline Theology class has been discussing the origins of Paul's anthropology recently. The question is usually framed as "Did Paul start with the problem (universal sin) and then find the solution (Jesus), or start with the solution (JC)and then construct the problem (sin)? I find this way of framing the question annoying, so have had a crack at putting together where I think Paul's anthropology comes from.

However the Jewish of the OT or 2nd Temple Judaism saw themselves, the Gentiles were always viewed as both culpable for their sin and enslaved to it (in idolatry). When Paul meets the risen Jesus on the Damascus road, he is forced to recognise him as the vindicated Messiah of God. If this is the case, then the Jewish authorities and people (including Paul himself) have numbered themselves with the Gentiles by fighting against the true Messiah. Yet this messiah offers Paul (and other Jews) forgiveness. This messiah has defeated the powers that enslave and taken the culpability on himself. If forgiveness is offered to Jews who have numbered themselves with the Gentiles, then it is likewise offered to Gentiles who act like true Jews by having Abrahamic faith.


I think it is from this framework that the connection with the OT is made. Paul pushes back beyond Sinai to Adam to show both Jew and Gentile under sin, he pushes back to Abraham to show Gentile and Jew under covenant, he goes back to the exile to show Jewish failure. Yet I don't think this comes simply from sitting down with the scriptures, but as a reflection on what has happened to the messiah.

So, theres my crazy thought for the day.
Takers, anybody?