Faith in generalissimos restored after purging rebellious masses (8)
I believe the answer is:
religion
'faith' is the definition.
('religion' can be a synonym of 'faith')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for religion that I've seen before include "Particular system of belief" , "Institution to express belief in a god" , "Belief in and worship of god or gods" , "Belief - way of life of monks and nuns" , "Institution for worship" .)