The best theology is rather a divine life than a divine knowledge.

Conduct is being ranked above doctrine. Whatever your convictions, they are tested by how you behave when it costs you something, and a person can hold an entire system correctly in their head while being unbearable to live with. The knowledge is comparatively easy to acquire, which is part of why it gets mistaken for the substance.

The same holds for any set of values, religious or not. Ask what somebody watching your ordinary week would conclude you actually believe, and compare that with what you would say if asked. Where the two differ, the week is the more reliable account.