Chapter 30 mentions that Sai's grace gives 'inconceivable great power.' Is this talking about worldly power, or something else?

Based on the context of Chapter 30, the "inconceivable great power" bestowed by Sai's grace refers to spiritual attainment rather than worldly might. The text immediately clarifies that this power manifests as "The wealth of discrimination between Self and non-Self" and the attainment of "all knowledge." This points to a profound inner transformation and enlightenment. The author himself provides an example: he feels unqualified to write the scripture, but through Sai's grace, Sai becomes the "illuminator of my speech" and the "capable lamp of knowledge," enabling the author to complete the sacred text. This demonstrates that the 'power' is the divine ability to transcend one's own limitations to achieve a higher spiritual purpose.