Prophet establishing a church in African nation (7)
I believe the answer is:
malachi
'prophet' is the definition.
(I know that Malachi is a prophet)
'a church in african nation' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'in' is an insertion indicator.
'african nation' becomes 'Mali' (country in Africa).
'a'+'ch'='ach'
'ach' inserted inside 'mali' is 'MALACHI'.
'establishing' acts as a link.
(Other definitions for malachi that I've seen before include "Hebrew prophet; OT book" , "Old Testament prophet" , "Good book" , "Part of Bible" , "8, Book 39" .)