Went to bed, exhausted by Bible lessons perhaps (7)
I believe the answer is:
retired
'went to bed' is the definition.
('retire' can be a synonym of 'go to bed')
'exhausted by bible lessons perhaps' is the wordplay.
'exhausted' becomes 'tired' (exhausted can mean very tired).
'by' says to put letters next to each other.
'bible lessons perhaps' becomes 'RE' (Religious Education).
'tired' after 're' is 'RETIRED'.
(Other definitions for retired that I've seen before include "Put out to pasture" , "Turned in" , "went back" , "Left" , "No longer active in work or profession" .)