According to the opening verses of Chapter 16, what are the key spiritual qualities of the Sadguru, and for what purpose did he take a physical form?

The beginning of Chapter 16 describes the Sadguru as the 'Stainless (Niranjana),' the 'Imperishable (Avyaya),' and the 'One beyond attributes (Gunatita).' He is hailed as the 'King of Yogis' whose sweet speech is like the nectar from the ocean of Vedanta. The text explicitly states the purpose for His incarnation, noting, 'You have taken this body for the sake of helping others, to uplift the poor and lowly.' This highlights that His physical manifestation is an act of compassion for the benefit of devotees.