Article of faith
I think it could be either:
'article of faith' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tenet that I've seen before include "Article of faith; doctrine" , "Matter of belief" , "A religious doctrine proclaimed as true without proof" , "It's believed" , "A belief or creed - a palindrome" .)
'article of faith' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dogma that I've seen before include "Non-evidence based opinion" , "Incontrovertible set of principles" , "Authoritative doctrine" , "Inflexible principles" , "Laid-down doctrine" .)