Favouring one kind of words for religious book (8)
I believe the answer is:
proverbs
'religious book' is the definition.
(Old Testament book)
'favouring one kind of words' is the wordplay.
'favouring' becomes 'pro' (I've seen this in other clues).
'one kind of words' becomes 'verbs' (**).
'pro'+'verbs'='PROVERBS'
'for' is the link.
(Other definitions for proverbs that I've seen before include "Old Testament book ascribed to Solomon, or well-known sayings" , "More than one saw" , "Book of the Bible" , "Truthful expressions" , "Adages, saws" .)