Music for church service (3,5)
I believe the answer is:
air force
'service' is the definition.
(I know that air force is a type of service)
'music for church' is the wordplay.
'music' becomes 'air' (air is a kind of music).
'church' becomes 'CE' (Church of England).
'air'+'for'+'ce'='AIR FORCE'
(Other definitions for air force that I've seen before include "Junior service" , "Country's military planes" , "Simple tune for church service" , "one of the services" , "A country's flying service" .)