The words of Allah used in a book or a novel (5)
I believe the answer is:
koran
'the words of allah' is the definition.
'in a book or a novel' is the wordplay.
'in' says the answer is hidden in the clue.
'KORAN' is hidden within 'book or a novel'.
'used' is the link.
(Other definitions for koran that I've seen before include "Sacred book of Islam with revelations of Muhammad" , "Sacred book of Islam (5)" , "Islamic sacred book" , "Islam's sacred book" , "Muslim holy book" .)