Encourage popular part of church (7)
I believe the answer is:
inspire
'encourage' is the definition.
(inspiring is a kind of encouraging)
'popular part of church' is the wordplay.
'popular' becomes 'in'.
'part of church' becomes 'spire'.
'in'+'spire'='INSPIRE'
(Other definitions for inspire that I've seen before include "Stimulate to creation" , "Breathe - fire" , "Fill a person with the urge to do something" , "Stimulate person to adventurous thought or deed" , "Breathe in and infuse into the mind" .)