How does the provided text explain the fundamental concepts of birth and death?

According to the teachings in Chapter 43, birth is described as the union of the body and senses, while death is their separation. These two events are considered inseparable from each other. The text further elaborates that death is a natural characteristic of the soul, whereas life is seen as a modification of the body. For enlightened beings who have transcended this cycle, such as saints who incarnate by their own will for the welfare of devotees, birth and death are considered to be false imaginations, as they have already overcome the fear and reality of physical mortality.