The purpose of Vamana avatar is to protect the devas who have been rendered homeless ever since Bali, having consolidated his powers, is reigning supreme over the three worlds. The Lord achieves this goal not by war or severe battle, nor by killing the opponent, but by assuming the charming form of a Brahmachari lad by which He is eligible to receive gifts from Bali, pointed out Sri B. Damodhara Dikshitar in a discourse.
Aditi, the mother of the devas, is aggrieved at the pitiable state of her sons. On the advice of Kashyapa, she propitiates Vishnu by observing the Payovrata vow for twelve days with devotional fervour. In response to her vrata, the Lord appears before her and promises to be born as her son. In due course, He is born as a divine child with the distinct marks of Vishnu on the auspicious day of confluence of Sravana and Dwadasi at the hour of Abhijit. He then transforms Himself into a Brahmachari boy, and the Upanayanam is performed by the rishis and celestials. He immediately proceeds to the yaga sala where Bali is performing the Aswamedha sacrifice. Clad in deer skin, with staff, umbrella and a jar of water, the Lord enters the sacrificial hall. With great joy Bali welcomes this guest of exceptional brilliance, washes His feet with love and devotion, and offers Him whatever He desires — earth, gold, houses, horses, elephants or chariots. Dana, is an important component in a sacrifice, and is much more than charity. It implies that the one who gives gifts absolves himself of all rights over what has been given to the one who receives. When Bali makes his offer, the Lord makes a humble request of a mere three steps of land. Though warned by Sukracharya, Bali does not re-track. The Lord rewards Bali’s selfless munificence with everlasting divine grace.
