The text says that a 'view of difference' leads to suffering. Can you explain this concept of duality and fear?

The teachings in Chapter 37 posit a direct link between duality and fear. It is stated that "where there is an obsession with duality, there fear enters." Anyone holding even a slight perception of difference or separation is said to fall into the sufferings of birth and death. This perception of manifoldness is rooted in ignorance (Avidya). The antidote prescribed is to "serve the non-distinguished state where there is not even a trace of fear." By holding firmly to the Guru's feet, one can be granted the "non-dual intellect," which allows one to see the underlying oneness of existence, thereby dissolving the very foundation upon which fear and suffering are built.