Briefly sample new sacred song (5)
I believe the answer is:
psalm
'sacred song' is the definition.
(religious song or hymn)
'briefly sample new' is the wordplay.
'briefly' means to remove the last letter.
'new' is an anagram indicator.
'sample' with its final letter taken away is 'sampl'.
'sampl' anagrammed gives 'PSALM'.
(Other definitions for psalm that I've seen before include "Lamps for a sacred song" , "Sacred poem attributed to David" , "Religious song" , "OT hymn" , "Sacred song of praise" .)