Acharya Prashant explains the concept of sacrifice as described in the Mundaka Upanishad and the Bhagavad Gita. He clarifies that true sacrifice is not merely the ritual of lighting a fire and offering oblations, but rather the practice of selfless action. This means performing one's duties without personal desire for the fruits of those actions. He emphasizes that when an individual works for a higher goal rather than for personal gain, their actions become a form of sacrifice that purifies the mind. This purification leads the mind to a divine state, metaphorically described as being taken by sunbeams to the abode of Indra. Unlike worldly actions where one seeks to accumulate, sacrifice is an act of losing one's ego and burdens to become lighter and more liberated.