Evaluate end of song in NT book (5)
I believe the answer is:
judge
'evaluate' is the definition.
(I know that evaluate is a more specific form of evaluate)
'end of song in nt book' is the wordplay.
'end of' indicates one should take the final letters.
'in' is an insertion indicator.
'nt book' becomes 'Jude' (Epistle of Jude is part of the New Testament).
The final letter of 'song' is 'g'.
'g' going inside 'jude' is 'JUDGE'.
(Other definitions for judge that I've seen before include "Form an opinion of" , "Deem; arbiter" , "Decide a legal case" , "Adjuicator" , "Assess" .)