How does the relationship between a Guru and disciple, as described by Baba, foster spiritual growth? Please use the gem and stone analogy from the text.

The relationship fosters growth through the disciple's focused devotion and the Guru's loving guidance. Chapter 19 explains that the Guru expects strong faith and the courage of patience from the disciple. To illustrate the outcome of this process, the text uses an analogy: both a stone and a gem are polished on a whetstone. While the process is the same for both, their inherent nature determines the result. The gem becomes a brilliant, sparkling diamond, while the stone, by its own nature, only becomes smooth. It cannot gain the luster of a gem. This implies that while the Guru provides the means for polishing, the disciple's own readiness and inner quality are crucial for achieving true brilliance and spiritual transformation.