Believers in God suffer His test (7)
I believe the answer is:
theists
'believers in god' is the definition.
'theists' can be an answer for 'believers' (theist is a kind of believer). I'm not sure about the 'in god' bit.
'suffer his test' is the wordplay.
'suffer' is an anagram indicator (I've seen 'suffering' mean this).
'his'+'test'='histest'
'histest' is an anagram of 'THEISTS'.
Can you help me to learn more?
(Other definitions for theists that I've seen before include "people who believe in God" , "religious people" , "Believers" .)