According to Chapter 19, what does a Guru truly expect from a disciple, and how is this illustrated?

The passages from Chapter 19 clarify that a true Guru, being desire-fulfilled, does not seek material wealth from a disciple. Instead, the Guru expects the disciple's wisdom, which manifests as 'strong faith at the Guru’s feet and the strength of courage which is patience.' This is the central expectation. The text uses an analogy to illustrate this point: just as a whetstone polishes both a common stone and a gem, the Guru's guidance works on the disciple. However, only the disciple with the inherent quality of a 'gem' (representing faith and patience) will become a 'brilliant jewel,' while a 'stone' remains merely smooth. This shows that the disciple's inner qualities are what the Guru values and works to refine.