Observe religious education with biblical book
I believe the answer is:
remark
'observe' is the definition.
('remark' can be a synonym of 'observe')
'religious education with biblical book' is the wordplay.
'religious education' becomes 're'.
'with' says to put letters next to each other.
'biblical book' becomes 'mark' (book of the Bible**).
're'+'mark'='REMARK'
(Other definitions for remark that I've seen before include "(E.g. Virgil's) pastoral poems" , "Written or spoken comment" , "Incidental observation" , "Notice; happen to say" , "Notice or comment on" .)