{If so be that God is one} (eiper heis ho theos). Correct
text rather than epeiper. It means "if on the whole." "By a
species of rhetorical politeness it is used of that about which
there is no doubt" (Thayer. Cf.  1Co 8:5  15:15  Ro 8:9 . {By
faith} (ek piste(9373)). "Out of faith," springing out of. {Through
faith} (dia t(8873) piste(9373)). "By means of the faith" (just
mentioned). Ek denotes source, dia intermediate agency or
attendant circumstance.