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

Chapter 47 employs a powerful metaphor involving the River Bhagirathi, also known as the Ganges. The text explains that while the Ganges purifies the world by washing away sins, it becomes soiled itself from this accumulation of impurities. To cleanse itself, the river desires the dust from the feet of saints, wondering, "When will the feet of saints touch me?" The chapter suggests that the river knows this is the only way to find deliverance from its own accumulated sins. This illustrates the supreme purifying power of saints like Sai, positioning them as even more potent than the most sacred river.