What is the philosophical concept regarding the unity of Saints discussed in Chapter 21?

Chapter 21 presents a profound spiritual concept about the nature of Saints. It posits that although Saints may take incarnations in different places and at different times for specific purposes, they are 'essentially inseparable from one another.' The text states that while their external circumstances like country and time may differ, they are inwardly all one. This suggests a universal, interconnected consciousness among enlightened beings. Chapter 21 mentions that the 'signs of one are known completely by another Saint,' implying a secret, inherent understanding and recognition among them, reinforcing the idea that they are all manifestations of the same divine principle.