According to Chapter 4 of Sai Satcharitra, what are the primary reasons saints incarnate on Earth?

Chapter 4 explains that saints incarnate on Earth primarily to address a widespread decay of religion and morality. When people lose their way, focusing only on worldly happiness from wealth and family and turning away from the ultimate spiritual goal, saints appear to reawaken religion. The text states they come to protect the system of castes and stages of life, destroy irreligion, and uplift the humble, poor, and weak. It is emphasized that saints are naturally liberated and have no self-interest; their incarnation is purely for the sake of others who are distressed and have missed the chance for self-upliftment.