Reduce sound for Bible reading (6)
I believe the answer is:
lesson
'bible reading' is the definition.
(I've seen this before)
'reduce sound' is the wordplay.
'reduce' becomes 'lessen' (I've seen this before).
'sound' indicates a 'sounds like' (homophone) clue.
'lessen' sounds like 'LESSON'.
'for' is the link.
(Other definitions for lesson that I've seen before include "15 down period" , "Instructive experience" , "Sermon or example" , "warning message" , "Portion of the scriptures read in church" .)