Refer to part of bible in speech for embellishment (13)
I believe the answer is:
ornamentation
'for embellishment' is the definition.
(synonyms)
'refer to part of bible in speech' is the wordplay.
'refer to' becomes 'name' (naming is a kind of refering to).
'part of bible' becomes 'nt' (New Testament abbreviation).
'in' means one lot of letters goes inside another.
'speech' becomes 'oration' (oration is a kind of speech).
'name'+'nt'='nament'
'nament' placed inside 'oration' is 'ORNAMENTATION'.
(Other definitions for ornamentation that I've seen before include "Decoration, embellishment" , "Decorative work" , "Adornment" , "Detailed artistic embellishment" .)