How does Chapter 4 characterize the nature of saints and their mission on Earth?

Chapter 4 portrays saints as beings who are naturally liberated but choose to incarnate on Earth for the benefit of others. Their mission is entirely selfless. They come to protect the systems of castes and stages of life, destroy irreligion, and safeguard the poor and weak. As the text explains, their purpose is to 'fill the foundation of Renunciation (Nivritti) and build the temple of Ultimate Truth.' They work to re-establish religion and awaken faith among people. Once their specific work is accomplished, their incarnation comes to an end.