Light seen by a lord quietly embracing religion (5,4)
I believe the answer is:
aldis lamp
'light' is the definition.
(Aldis lamp is a type of signal light)
'a lord quietly embracing religion' is the wordplay.
'lord' becomes 'ld' (abbreviation for the aristocratic title).
'quietly' becomes 'p' (p for piano and quiet).
'embracing' is an insertion indicator.
'religion' becomes 'islam' (Islam is an example).
'ld'+'p'='ldp'
'ldp' enclosing 'islam' is 'ldislamp'.
'a'+'ldislamp'='ALDIS LAMP'
'seen by' is the link.
(Other definitions for aldis lamp that I've seen before include "shiner" , "Hence flashes with meaning" .)