Patriarch's account in prophetic book (5)
I believe the answer is:
jacob
'patriarch's' is the definition.
'account in prophetic book' is the wordplay.
'account' becomes 'ac'.
'in' is an insertion indicator.
'prophetic book' becomes 'job' (book of the Bible).
'ac' placed inside 'job' is 'JACOB'.
(Other definitions for jacob that I've seen before include "Father of the twelve patriarchs of Israel" , "Rachel's husband" , "He had a vision of a ladder into heaven with angels going up and down it" , "man" , "-- Rees Mogg, MP" .)