Based on the teachings in Chapter 4, why do saints, who are already liberated, choose to descend to the world of mortals?

Chapter 4 of the Sai Satcharitra provides a clear explanation for this. It states that saints, while naturally liberated themselves, are always ready to uplift the distressed. Their incarnation is described as being purely for the sake of others, with no personal self-interest involved. They descend to the mortal world when religion is in decay and people have lost their way, obsessed with materialism and sensual pleasures. The purpose of their advent, as detailed in the chapter, is to protect the humble and weak, destroy irreligion, and re-establish the system of castes and stages of life to guide humanity back to its ultimate well-being.