According to the source, what is the nature of a Sadguru and how should a disciple behave towards them?

Chapter 16 describes the Sadguru as one whose desires are already fulfilled (Aptakama) and who has taken a physical form to uplift the poor and lowly. For a disciple, the most important conduct is to surrender completely, as the Guru knows the disciple's pitfalls and provides remedies. The chapter strongly advises against using 'cleverness' or showing any neglect in service, emphasizing that firm faith at the Guru's feet is essential. Even a simple leaf offered with faith is accepted with love, but offerings made with pride are rejected. Ultimately, the path to union with Brahman is through humble service to the Guru.