If so be that God is one (eiper ei o qeo). 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. 1 Corinthians 8:5 ; 1 Corinthians 15:15 ; Romans 8:9 . By faith (ek pistew). "Out of faith," springing out of. Through faith (dia th pistew). "By means of the faith" (just mentioned). Ek denotes source, dia intermediate agency or attendant circumstance.