What philosophical concept regarding the nature of Saints is introduced in Chapter 21?

Chapter 21 introduces the advanced philosophical concept of the fundamental unity of all Saints. The text explains that although Saints may take incarnations in different places and at different times for specific purposes, "they are essentially inseparable from one another." This implies a shared consciousness and purpose that transcends physical form and location. According to Chapter 21, "Country, time, and objects may differ, but the signs of one are known completely by another Saint; Inwardly, they are all one." This teaching points to a secret, divine arrangement where all true masters are interconnected parts of a single spiritual entity, working in unison for the world's welfare.