What’s exactly divine power?
Being a power that opposed insanity, a power brought forth by intense magic energy, initially I personally thought that it would have been associated with its counter part, spirit energy,
But on the Theurgist set we see in the description how the previous user is described as a powerful “mage”.
Now, in AO mage may be a widely used word, but it usually has a common factor, the use of magic.
There is also the fact that insanity seems also linked to strong resentment and negative emotions, something also associated with magic energy or at least its origin, chaos.