God wants daughter to protect bird forever (8)
I believe the answer is:
eternity
'forever' is the definition.
(synonyms)
'god wants daughter to protect bird' is the wordplay.
I cannot quite understand how this works, but
'bird' could be 'tern' (tern is a kind of bird) and 'tern' is present in the answer.
This explanation may well be incorrect...
(Other definitions for eternity that I've seen before include "Endless duration" , "That's a very long time" , "Endless time" , "An extremely long time" , "Wolfgang Amadeus -" .)