Motivate one part of church after end of sermon (7)
I believe the answer is:
inspire
'motivate' is the definition.
(thesaurus)
'one part of church after end of sermon' is the wordplay.
'one' becomes 'i' (Roman numeral).
'part of church' becomes 'spire'.
'after' is a charade indicator (letters next to each other).
'end of' suggests the final letters.
The last letter of 'sermon' is 'n'.
'spire' put after 'n' is 'nspire'.
'i'+'nspire'='INSPIRE'
(Other definitions for inspire that I've seen before include "Fill someone with a feeling of confidence to do something" , "Uplift" , "Fill with creative purpose" , "Encourage - animate - draw into the lungs" , "Fill with ideas, enthusiasm" .)