Faith, we hear, is tied up (7)
I believe the answer is:
trussed
'is tied up' is the definition.
(I've seen this in another clue)
'faith we hear' is the wordplay.
'faith' becomes 'trust' (synonyms).
'we hear' shows a homophone (sound like).
'trust' sounds like 'TRUSSED'.
(Other definitions for trussed that I've seen before include "Dusters (anag) - bound" , "Bundled up" , "Secured" , "with restrictions on members" , "Tied up" .)