One's opening book of Bible, absolutely excellent (9)
I believe the answer is:
exquisite
'excellent' is the definition.
(I know that excellent can be written as exquisite)
'one's opening book of bible absolutely' is the wordplay.
'one's' becomes 'I's' (Roman numeral).
'opening' indicates putting letters inside (some letters open a gap in others).
'book of bible' becomes 'Ex' (abbreviation for Exodus).
'absolutely' becomes 'quite' (I've seen this in another clue).
'ex'+'quite'='exquite'
'is' going inside 'exquite' is 'EXQUISITE'.
(Other definitions for exquisite that I've seen before include "Lovely" , "Of the highest excellence" , "delicate" , "Delicious" , "Extremely beautiful" .)