Based on Chapter 5, what is the philosophical importance of overcoming pride and achieving a state of non-duality for spiritual advancement?

Chapter 5 of the Sai Satcharitra emphasizes that self-imagined cleverness is useless for spiritual welfare; one must act without pride. The text states that he who has "burned the pride of the body has made this body meaningful" and can then become a disciple to achieve the supreme goal. This leads to a state of non-duality, which is likened to the sun being unable to enter darkness. For such a wise person, their own form is the entire universe, and they reside in non-duality, free from the sense of being a separate doer of karma. This desireless state is the key to climbing the "fort of selflessness."