Costume has bible class in shock (7)
I believe the answer is:
apparel
'costume' is the definition.
(I've seen this before)
'bible class in shock' is the wordplay.
'bible class' becomes 're' (Religious Education).
'in' is an insertion indicator.
'shock' becomes 'appal' (synonyms).
're' placed into 'appal' is 'APPAREL'.
'has' is the link.
(Other definitions for apparel that I've seen before include "costume" , "formal dress?" , "Real pap (anag) - clothing" , "Raiment" , "Garb, clothes" .)