Acharya Prashant explains the profound meaning of a couplet by Kabir Saheb, emphasizing the nature of an unchanging internal flame or 'lau'. He describes this state as a constant, unwavering light that remains unaffected by the external world's continuous changes, such as time, age, relationships, and emotions. This internal light provides a deep sense of assurance and peace because it is immutable. He suggests that true living begins only when one finds something within that remains untouched by worldly experiences, whether they are sweet or bitter, high or low. When one identifies with this light rather than the changing 'Prakriti' (nature), they transcend their personal identity and merge with the infinite existence, becoming a witness to the world's fluctuations without being disturbed by them.