What is the philosophical nature and mission of saints as outlined in Chapter 4?

Chapter 4 presents the nature of saints as being inherently liberated beings whose incarnation is purely for the benefit of others, with no self-interest involved. They descend to protect the system of castes and stages of life and to destroy irreligion. Their mission, as described in this chapter, is to fill the foundation of Renunciation (Nivritti) and build the temple of Ultimate Truth. In doing so, they uplift devotees by performing the work of religion and awakening faith. Once their specific, divine work is fulfilled, they conclude their incarnation.