Valley welcoming a theologian to provide cheer (7)
I believe the answer is:
gladden
'cheer' is the definition.
(thesaurus)
'valley welcoming a theologian' is the wordplay.
'valley' becomes 'glen' (glen is a kind of valley**).
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'theologian' becomes 'dd' (Doctor of Divinity degree).
'a'+'dd'='add'
'glen' going around 'add' is 'GLADDEN'.
'to provide' acts as a link.
(Other definitions for gladden that I've seen before include "Fill with joy" , "Lift (the heart)" , "Dangled (anag) - cheer" , "Give pleasure to" , "raise spirits" .)