Acclamation in church always before start of sermon (6)
I believe the answer is:
cheers
'acclamation' is the definition.
'church always before start of sermon' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'always' becomes 'eer' (poetic way of saying ever).
'before' means one lot of letters go next to another.
'start of' says to take the initial letters.
The initial letter of 'sermon' is 's'.
'ch'+'eer'+'s'='CHEERS'
'in' is the link.
(Other definitions for cheers that I've seen before include "Expression of gratitude" , "Applauds" , "Bottoms up; thanks" , "Word often said before drinking" , "Good health!" .)