Can you explain the concept of non-duality and the merging of a devotee with the Guru as described in Chapter 40?

Chapter 40 explains the advanced spiritual concept of non-duality through a simple, beautiful analogy. It compares the devotee and the Guru to a river and an ocean. While they have different names and forms, they are essentially the same in substance (water). When the river meets the ocean, any distinction is lost, and they become one. In the same way, the chapter teaches that when a devotee seeks 'exclusive refuge in the Sadguru with devotion,' Sai destroys the sense of duality—the separate feelings of 'me' and 'you.' By embracing them, He grants them His own 'Guru-nature,' dissolving the separation and making them one unified consciousness.