What is the primary purpose of a saint's incarnation on Earth, according to the teachings in Chapter 4 of Sai Satcharitra?

According to Chapter 4 of the Sai Satcharitra, the incarnation of saints is a divine response to a period of societal and religious decay. Saints descend to the mortal world when religion is in decline, when people lose sight of the ultimate goal (Paramartha), and are consumed by worldly desires. The text states that their arrival is to awaken religion, protect the system of castes and stages of life, and destroy irreligion. It is emphasized that saints, who are naturally liberated, undertake this mission purely for the sake of others, particularly to uplift the distressed, humble, poor, and weak. Their incarnation serves no self-interest and is entirely dedicated to the well-being and spiritual upliftment of humanity.