What is the primary theme of Chapter 15 concerning the relationship between Sai and his devotees?

The primary theme of Chapter 15 is the powerful dynamic between a devotee's persistent love and the Guru's compassionate response. The chapter explicitly states its purpose is to describe how Sai, being pleased by the prayers of his loving devotees, grants them his vision. This theme is powerfully conveyed through the metaphor of the mother cat and her kittens. As detailed in Chapter 15, the kittens' unwavering affection eventually overcomes the mother's initial resistance, causing her love and nourishment to flow freely. This suggests that a devotee's sincere and persistent prayer will ultimately be met with divine grace and vision.