Hello, stop stuffing fish in a place of worship! (4,5)
I believe the answer is:
high altar
'a place of worship' is the definition.
(altar in a church)
'hello stop stuffing fish' is the wordplay.
'hello' becomes 'hi' (synonyms).
'stop' becomes 'halt' (halt can mean to stop).
'stuffing' indicates putting letters inside.
'fish' becomes 'gar' (gar is a kind of fish).
'halt' inserted into 'gar' is 'ghaltar'.
'hi'+'ghaltar'='HIGH ALTAR'
'in' is the link.
(Other definitions for high altar that I've seen before include "part of church" , "Principal church table" .)