What is the primary cause of being trapped in the cycle of birth and death, and how does it relate to the concept of Brahman?

The primary cause of being trapped in the eternal cycle of worldly existence (Samsara), with death following birth and rebirth following death, is a deluded perception of separation. As explained in Chapter 37, this cycle continues for one who believes, "Parabrahman is different from me; I am not that, I am something else." This 'knowledge of difference' stems from ignorance. The text clarifies that the same divine principle, Brahman, pervades everything from the creator down to a blade of grass. It only appears to be different from the Self when combined with adjuncts (upadhis) in the mind of a soul deluded by ignorance.