Can you explain the metaphor of the River Bhagirathi (Ganges) that is used at the beginning of Chapter 47?

In Chapter 47, the River Bhagirathi, also known as the Ganges, is used as a powerful analogy to demonstrate the supreme purifying power of saints. The text describes that while the Ganges washes away the sins of the world, she becomes soiled herself with these accumulated impurities. To find her own purification, she yearns for the dust from the feet of saints. As the chapter explains, she knows there is no other deliverance from her own burden of sins. This metaphor, found in the opening verses of Chapter 47, powerfully establishes the elevated spiritual status of saints like Sai Baba, whose grace is sought even by sacred entities.