How does Chapter 40 explain the concept of destroying duality and the unity between a Guru and devotee?

Chapter 40 provides a beautiful explanation of non-duality, particularly in the context of the Guru-devotee relationship. It states that Shri Sai Samarth has the power to destroy the sense of duality, dissolving the separate feelings of "me" and "you." When a devotee seeks exclusive refuge, Sai embraces them and grants them His own Guru-nature. The text uses a powerful analogy to illustrate this union: just as a river and an ocean have different names but are essentially one and lose all difference when they meet, so too does the devotee merge with the Sadguru. This chapter emphasizes that Sai makes the unattainable attainable by eliminating this very sense of separation.