The phrase "abiding belief" means having a strong, unwavering conviction or faith in something. It refers to a deep and lasting belief that remains constant over time. Full definition
There are many people who can have a sincere and abiding belief in something they can neither demonstrate nor give evidence of. (religion.blogs.cnn.com)
Outlining her qualities, «hard work, discipline, capacity for detailed research, intimate knowledge of the law, independence of mind and spirit, honesty and integrity, deep - seated respect for the rule of law and for the best traditions of the legal profession, abiding belief in the sovereignty of Almighty God», the President stated that these will serve her well in her new office. (ghanapoliticsonline.com)
«As an Egyptian immigrant who was taken under the wing of a great business leader like Bill Campbell, I have an abiding belief that we all should pay it forward by ensuring that our workplace represents all types of people,» Michael wrote. (businessinsider.com)