Bible book briefly picked up before end of religious service (4)
I believe the answer is:
mass
'service' is the definition.
(religious service)
'bible book briefly picked up before end of religious' is the wordplay.
'bible book briefly' becomes 'Sam' (abbreviation for the Book of Samuel).
'picked up' shows that the letters should be reversed in order.
'before' is a charade indicator (letters next to each other).
'end of' suggests the final letters.
The last letter of 'religious' is 's'.
'sam' written backwards gives 'mas'.
'mas'+'s'='MASS'
(Other definitions for mass that I've seen before include "Service; horde" , "Total" , "Christian ritual" , "congregation for > service" , "Holy service" .)