1. St. Paul said that the Mosaic Law was good and holy (Romans 7:12). If you're a Christian, you can't disregard the Old Testament, and neither can you disregard the Old Law (though you are not bound to the juridicial and ceremonial precepts). You must grant the justice of these commandments, since they come from a God who is Justice Itself.
As a Christian I am governed by the spirit of Christ: love, forgiveness, kindness, generosity, etc., not Jewish religious laws. So my take on the OT commandments is that they are relevant to the extent that they reflect the spirit of Christ. Otherwise they are a Jewish matter.
Nothing Paul wrote changes that for me.
2. You dodged my question about Hell. How can you explain everlasting punishment solely in terms of "pragmatic" considerations?
Being human, I have no idea what is "everlasting" and what isn't. Being human, I do not have the capacity to see into the hearts and minds of other people clearly enough to assess their guilt or determine a just punishment. So all I can do is deal with them as reasonably and pragmatically as I'm able. I think of it as something akin to 'triage'.
