Can you explain the significance of the River Ganges metaphor used in Chapter 47?

The metaphor involving the River Ganges (Bhagirathi) in Chapter 47 is used to exalt the spiritual stature of saints like Sai Baba. The chapter explains that the Ganges, revered for washing away the sins of the world, becomes soiled herself from these impurities. To achieve her own purification, she desires the dust from the feet of saints, knowing that "without this, there is no deliverance from her sins." This analogy, as presented in Chapter 47, powerfully conveys that the purifying power of a true saint transcends even that of the holiest natural elements. It positions saints as the ultimate source of purification and liberation, capable of cleansing even the cleanser.