General:
* Orthodox: This is the most common and direct word, implying adherence to established beliefs and practices.
* Conforming: A neutral term simply indicating compliance with a set of rules or principles.
* Adhering: Similar to conforming, but suggesting a stronger commitment to the doctrine.
* Observant: This implies following the doctrine diligently and meticulously.
More specific:
* Dogmatic: This word implies a rigid adherence to the doctrine, sometimes to the point of being inflexible.
* Traditional: This emphasizes the historical and established nature of the doctrine.
* Canonical: This is specific to religious doctrines and refers to what is considered official and accepted.
* Prescribed: This implies that the doctrine is laid out and enforced by an authority.
* Compliant: This focuses on the act of following the doctrine without questioning it.
The best word will depend on the specific context and the desired emphasis.