Collects are primarily associated with church services (7)
I believe the answer is:
amasses
'collects' is the definition.
('amass' can be a synonym of 'collect')
'primarily associated with church services' is the wordplay.
'primarily' says to take the initial letters.
'with' is a charade indicator (letters next to each other).
'church services' becomes 'masses' (Mass is a type of church service).
The initial letter of 'associated' is 'a'.
'a'+'masses'='AMASSES'
'are' acts as a link.
(Other definitions for amasses that I've seen before include "Gathers together" , "'Accumulates, gathers (7)'" , "Collects" .)