Can you explain the metaphor of the River Bhagirathi (Ganges) as used in Chapter 47?

Chapter 47 uses a powerful metaphor involving the River Bhagirathi, also known as the Ganges, to illustrate the purifying power of saints like Sai Baba. The text explains that while the river washes away the sins of the world, it becomes soiled with these accumulated impurities itself. To cleanse herself, the river desires the dust from the feet of saints. It longs for the moment when saints will come to bathe in her waters, knowing that this is the only way for her to be delivered from her own burden of sins. As detailed in Chapter 47, this analogy highlights the supreme holiness of saints, whose presence can purify even the most sacred purifiers.