Service man licensed by bishop to brew dreary ale (3,6)
I believe the answer is:
lay reader
'service man licensed by bishop' is the definition.
(a lay reader helps in a religious service)
'brew dreary ale' is the wordplay.
'brew' indicates anagramming the letters.
'dreary'+'ale'='drearyale'
'drearyale' is an anagram of 'LAY READER'.
'to' acts as a link.
(Other definitions for lay reader that I've seen before include "One not ordained but licensed to preach" , "who may give lessons" , "licensee in church" , "Parish assistant" , "who carries out some services" .)