Come together for religious service (4)
I believe the answer is:
mass
I believe this clue is a double definition.
'come together' is the first definition.
(I've seen this in another clue)
'for religious service' is the second definition.
(I've seen this in another clue)
(Other definitions for mass that I've seen before include "Accumulation" , "Large amount, body" , "Heap; religious service" , "load" , "Bulk - RC service" .)