What is the relationship between the Soul and the body as described in the text, and why does it cause the cycle of worldly existence?

According to the philosophy in Chapter 19, the Soul (Atma) and the body have a paradoxical relationship. By nature, they are different; the Soul is changeless and imperishable, while the body is perishable. Despite this, their affection is described as extraordinary, and one cannot bear to be without the other. The text explains that it is precisely because of this immense love and inseparable union that the cycle of worldly existence, or Samsara, continues. This relationship is presented as a supreme, unavoidable exception to the rule that friendship typically exists only between those of similar nature.