"Secular" Vs. "Relgious" Use of *pistis* in NT Greek

(I've posted this question before, but received a good, but small, amount 
of wisdom from the net (thanks).  Perhpas I phrased it badly)

I've been struck by the division a number of scholars make in their
discussions of *pistis* (e.g. Gerhard Barth, D. Lindsay) between the
'religious' and 'secular' uses of the term.

The basis of this division seems puzzling.  Sometimes, it seems to be 
simply a question of whether God is also mentioned in the sentence (!), 
sometimes it seems that 'ethical, moral' uses of the word count as
'secular'(e.g. Tit 2.9-10, 1 Tim 5.11-12), whilst those more ameniable to 
faith as understood in modern liberal protestantism (e.g. Bultmann, Ebeling)
as automatically declared 'religious'.  Is it more about how the particular
scholar conceives our response to God, than about historical linguistics?

Are there any linguistics on these lists who might be able to tell me
what basis there is for this distinction, and what worth it has as a 
serious heuristic tool?  (please!),

Thanks for your patience,



Timothy Gaden