The source material mentions a 'knot in the heart.' What is this, and what is the prescribed method, including the need for patience, to untie it?

The 'knot in the heart' is explicitly defined in Chapter 37 as the firm 'body-consciousness'—the mistaken belief that 'Body is me, this is my wealth.' This knot is identified as the dwelling place of Maya's sorrow and the source of desires that fuel the cycle of rebirth. To untie this knot, one must destroy desires at their very root. This is accomplished through Brahma-Jnana (knowledge of Brahman), which is called the 'pure remedy.' However, this spiritual work is not possible without key virtues. As the great Guru Sai Nath states, 'full faith and patience' are essential, and with even 'a little patience of faith,' one can achieve this liberation and become immortal.