Gather together great number in a religious service (5)
I believe the answer is:
amass
'gather together' is the definition.
(I've seen this before)
'a religious service' is the wordplay.
'religious service' becomes 'mass' (I've seen this in another clue).
'a'+'mass'='AMASS'
'great number in' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for amass that I've seen before include "Gather together, pile up" , "Collect, hoard" , "Accumulate, heap up" , "run up?" , "Collect or gather" .)