MAF,
Sorry for being obscure...
"Christianity" is not really at stake, as it was still in the making when those words were written (and the so-called Pauline writings were going to be a big part of the process).
What I meant is that these "rhetorical questions" are actually the deepest criticism levelled at Jewish monotheism from a definite standpoint, which I might provisionally call "early gnosticism".
Such as: how can the one and same "God" be really creator, in the highest sense of the term (i.e., the forger of everyone's destiny, according to the potter comparison), and judge? How can he be both the righteous lawgiver and savior of anyone?
The questions actually tend to a solution where the "Savior" is not thought of as a creator, judge or lawgiver anymore...
Something similar happens in 1 Corinthians: if we presently experience a "spiritual" resurrection which connects us with "God", "eternity" or whatever, what need is there for a "real resurrection" in the future? Saying that the former proves the latter, as Paul does, is logically desperate (btw, the argument will be completely dropped in Romans).
The questions are good. The answers are nonexistent or pathetic IMO, just because the author does not want to go too far along these lines. But he does open boxes which are very difficult to close...
By "post-christian" I mean acknowledging the inheritance of Christianity without being able to share its common beliefs any longer... a very common status nowadays I guess...