According to Chapter 19, what is the nature of the relationship between the Soul (Atma) and the body, and why does this lead to the cycle of Samsara?

Chapter 19 describes the union of the Soul (Atma) and the body as a 'supreme, unavoidable exception' to the rule that friendship exists between those of similar nature. The text highlights their fundamental differences: the body is perishable, while the Soul is changeless and imperishable. Despite this, their affection for each other is described as extraordinary, to the point where they cannot bear to be apart. According to the teachings in this chapter, it is precisely this immense love and attachment between the imperishable Soul and the perishable body that perpetuates the cycle of worldly existence, or Samsara.