The story of the burning of Tripura, narrated by Narada in the Bhagavata Purana, is symbolic of the invisible and powerful sway of delusion that every individual has to fight against to gain spiritual wisdom, pointed out Nochur Sri Venkataraman in a discourse.
Once during a conflict between celestial beings and asuras, the former, with Vishnu’s support became powerful, and the demons sought refuge with Mayan, the master of all magical arts. He built three flying fortresses of gold, silver and iron which came to be known as Tripura. The demons could now move about invisibly in these fortresses which had incredible kinds of weapons with which they began to destroy everything.
The celestial beings, unable to withstand the onslaught, approached Rudra for assistance. Rudra shot arrows with divine powers and brilliance at the three fortresses which penetrated Tripura and the demons succumbed. Mayan came to their rescue again by creating a pond of nectar which rejuvenated the demons. The resurrected asuras persisted with their atrocities.
On seeing a despondent Rudra, Vishnu took the form of a cow and Brahma that of a calf and drank up all the nectar from the pond.
Then Vishnu bestowed on Rudra new weapons, chariot, charioteer, and all other necessary equipment so that he could fight the demons who were now vulnerable. Rudra waited for the auspicious hour known as Abhijit to fell the invincible fortresses and asuras.
Vedanta truths are of a subtle nature and so are the ways in which they are transmitted. The three fortresses represent the make-believe appearances and experiences of the Self in the three states of consciousness — waking, sleep and deep sleep. The unchangeable reality is the witness behind the three states. In all these states, the Self is ever present though remaining unknown.
But because of ignorance, the Self identifies with these transitory experiences and does not realise its own pure and free nature. A mirage conjures up the appearance of water in very convincing terms from a distance.