How does the analogy of the gem and the stone illustrate the role of patience and faith in a disciple's development?

The analogy of the gem and the stone, found in Chapter 19, powerfully illustrates how a disciple's inner disposition affects their spiritual growth. Both a stone and a gem can be rubbed on a whetstone, representing the Guru's guidance and teachings. However, while the stone merely becomes smooth, the gem transforms into a brilliant jewel. This signifies that the Guru's process is applied to all, but the outcome depends on the disciple's inherent qualities. The text clarifies that a Guru expects "strong faith at the Guru’s feet and the strength of courage which is patience." A disciple with these qualities is like the gem, capable of being polished into brilliance. Without them, one remains like the stone, unable to gain the same luster despite receiving the same treatment.