According to the teachings, what is the relationship between desires, the 'knot in the heart,' and the cycle of rebirth?

The teachings in Chapter 37 explain that the firm 'body-consciousness'—the belief that 'Body is me, this is my wealth'—is the knot in the heart and the source of sorrow. This chapter elaborates that desires are like seeds from which rebirth is obtained, perpetuating a cycle that moves with unhindered speed. To end this cycle, desires must be destroyed at the root. Only when these seeds of action are completely burned does the knot in the heart get removed, allowing a mortal to become immortal, as taught in the Vedanta.