Society is not safe from this religious gatekeeper (5,5)

'this religious gatekeeper' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?

'society is not safe' is the wordplay.
'society' becomes 's' (common abbreviation in names of organisations).
'is not' becomes 'ain't' ('ain't' is a non-standard form of 'isn't').
'safe' becomes 'peter' (slang term for a safe).
's'+'aint'+'peter'='SAINT PETER'

'from' is the link.

Can you help me to learn more?