Based on the opening verses of Chapter 16, what is the fundamental nature of the Sadguru and the reason for His physical incarnation?

The beginning of Chapter 16 praises the Sadguru, Sai Baba, with profound titles, calling him the 'Stainless (Niranjana),' the 'Imperishable (Avyaya),' the 'One beyond attributes (Gunatita),' and the 'King of Yogis.' This establishes his divine, eternal, and transcendent nature. The chapter explicitly states the purpose of his physical form, explaining, 'You have taken this body for the sake of helping others, to uplift the poor and lowly.' This highlights that his incarnation is an act of supreme compassion, intended to guide and elevate humanity, especially those who are struggling and in need of spiritual support, as detailed in Chapter 16.