Chapter 19 discusses the relationship between the soul and the body. Can you explain their different natures and why their union is considered an 'unavoidable exception'?

The teachings in Chapter 19 describe a profound yet paradoxical relationship between the soul (Atma) and the body. It states that while the general rule is that 'friendship exists between those of similar nature,' the union of the soul and body is a supreme exception. This is because their natures are entirely different: the body is perishable and transient, while the soul is changeless and imperishable. Despite this fundamental difference, their affection is described as extraordinary, with one unable to bear being without the other. As Chapter 19 explains, this immense love is what perpetuates the cycle of worldly existence, or Samsara.