The Jewish doctrine holds that a man can at any time return and be accepted by God. That is all. The simplicity of this idea is deceptive. Let us translate it into a language closer to Christianity, while noting that Buber refrains from doing this: God can at any time forgive those who repent.Matin Buber, I and Thou, tr. Walter Kaufmann (Touchstone: New York 1970), p. 36-37.
This conception of return has been and is at the very heart of Judaism, and it is for the sake of this idea that Jonah is always read on the highest holiday of the year [Yom Kippur]. But the theology of Paul in the New Testament is founded on the implicit denial of this doctrine, and so are the Roman Catholic and the Greek Orthodox churches, Lutheranism and Calvinism. Paul's elaborate argument concernirtg the impossibility of salvation under the Torah ("the Law") and for the necessity of Christ's redemptive death presuppose that God cannot simply forgive anyone who returns.
If the doctrine of the return is true, Paul's theology collapses and "Christ died in vain." Nor does any need remain for baptism and the sacrament of confession, or for the bread and the wine. Man stands in a direct relationship to God and requires no mediator.
And I'm lodging it here to invite rumination. I have a few of my own, largely centered around the 4th century concept of "atonement," but I want to review a few resources on Romans before I start my end of the discussion.
So, for those interested, I leave it to you.
One challenge I would raise, as would many a New Testament scholar: the "theology" of Paul? Reading his letters carefully, it's not clear he ever had one, certainly not in the "systematic" sense we would mean, post-Tillich. That is more than a quibble, but perhaps, ultimately, not much more.