One part of the Bible with biblical hero, verily (2,5)
I believe the answer is:
in truth
'verily' is the definition.
(I've seen this in another clue)
'one part of the bible with biblical hero' is the wordplay.
'one' becomes 'I' (Roman numeral).
'part of the bible' becomes 'nt'.
'with' is a charade indicator (letters next to each other).
'biblical hero' becomes 'Ruth' (Old Testament figure).
'i'+'nt'+'ruth'='IN TRUTH'
(Other definitions for in truth that I've seen before include "To be honest" , "As a matter of fact" , "Actually" , "Honestly" , "Really" .)