"Be engrossed in Lord Siva at all times". --This is in essence is the message of Nanthi to us. His posture facing the sanctum and sanctorum of Siva temples reminds us of this message.
Hindus attach great sanctity to Nanthi, the flag and vehicle of Lord Siva. Nanthi is venerated since it represents God Himself. That is why we call him 'nanthiemperuman'.
Lord Siva is love and love is god. Therefore, Nanthi flag personifies love itself. Other values that Nanthi stands for are sacrifice, devotion, detachment, perception, tolerance, humility, service and what is more, it is hailed as God himself. Therefore, Nanthi Flag signifies all such lofty values of the Saivaites. That, really, is the significance of the Nanthi flag.
It is in such a context that the World Saiva Council has declared Sivarathri Day, a sacred day of Hindus for the worship of Lord Siva, as the Flag Day. In as much as each religion has a flag of its own, Saivaites, too hoist Nanthi flag to express their entity for Nanthi is both the vehicle and the flag of Lord Siva, the almighty god of the Saivaites.
Nanthi Flag thus brings hundreds of Hindus under one umbrella. That is precisely why we find Nanthi flag being unique so that we Hindus, are not compartmentalized. It portrays unity in diversity, the oneness of the humanity. In all temples of Siva, the annual festival commences with the hoisting of Nanthi Flag, and it flies throughout the festival. In addition the Nanthi flags are hoisted in all Hindu temples and their premises during Hindu festivals.
Nanthi Flag is associated with the religious and cultural lives of the Hindus. Whenever and wherever Lord Siva appeared before his ardent devotees to bestow a boon, He gave darshan appearing on his vehicle Nanthi.
When Saint Gnanasampanthar had Lord Siva's dharshan for the first time in his infancy, he saw Lord Siva with his Consort on his vehicle Nanthi. It has been so with all saints and devotees. Saint Manicavasagar portrays Lord Siva holding Nanthi Flag through his dialogue with the parrot in one of his celebrated hymns, Thiruvasagam. I give below a translation by G.U Pope
Green Parrot of the grove
Declare what banner
The glorious waves
Above the king of Parunthrai's
The stainless banner of the bull
In beauty manifests
While foes flee far
In another stanza in Thiruchalal in Thiruvasagam, Nanthanar raises a query as to why Lord Siva preferred nanthi to all other vehicles, elephants, horses or cars which are stately at times. He himself gives the answer that Nanthi is preferred by Lord Siva for it represents Vishnu supporting the chariot.
Here is the stanza and its English translation.
On stately elephant swift stead or car
It pleased him not to ride
A bull He pleased to mount
Explain me this that I may know,
The day He burnt with fire
The triple mighty walls
Mal divine become to bear him up
In all temples of Siva, Nanthi is situated facing the Sanctum Sanctorum always mediating upon Lord Shiva. Thus Nanthi conveys a message to the devotees to be engrossed in God at all times. Nanthi occupies a special place in the life of Hindus.