According to Chapter 21, what is the nature of Saints and their incarnations, and how are they connected to one another?

Chapter 21 explains that Saints take incarnations from time to time in various places they like, for specific purposes. However, the text emphasizes a profound unity among them, stating they are "essentially inseparable from one another." Even if their country, time, and circumstances differ, the signs of one Saint are completely known by another. This chapter beautifully illustrates that inwardly, all Saints are one. This union with Saints, the author notes, is not easily accessible to the unfortunate and is only attained when God’s grace is present.