Can you explain the concept of 'undivided faith' and its rewards as described in the provided text?

The concept of 'undivided faith' refers to a steadfast and unwavering devotion to Sai Baba. Chapter 33 concludes with a powerful assurance for such devotees. It states that for a devotee with 'undivided faith,' Sai is capable of granting the fruit of any desire, whether it is 'worldly or spiritual.' This suggests that the key to receiving grace and having one's purposes fulfilled lies in the quality of one's faith. The stories of Haribhau Karnik and Appasaheb serve as illustrations of how Sai interacts with his devotees, testing and ultimately rewarding their faith, showing that when devotion is pure, Sai helps them achieve their goals.