When Indra’s rajya is taken over by Mahabali, his mother Aditi asks her husband sage Kashyapa for a solution. He asks her to observe payo vrata in the month of Phalguna, beginning from Sukla paksha, prathama and continue it for 13 days until trayodasi. She must offer milk porridge to Vishnu, and at the end of the vrata, Vishnu will appear as her son. Only He can recover Indra’s rajya from Mahabali, says the sage. Aditi observes the vrata, and Vishnu is born as her son. This happens in the month of Shraavana, in the star Sravana, on Dvadasi. The baby grows up at once into a boy of about seven years. Why does the Lord assume a short stature when He goes to meet Mahabali? He has to impress Mahabali, and find a soft spot in his heart. What better way to do this than to assume the form of a child?
In the Divya Prabandham, there are many verses which extol the loveliness of Krishna and Vamana in the same verse, said M.A. Venkatakrishnan in a discourse. Both were children; both were attractive. Yasoda, in one verse, even addresses Krishna as ‘Vamana nambi.’ Kamban says that Vamana’s form was adhbhuta — a form to marvel at. Only jnanis could understand His sukshma roopa. Mahabali was taken in by the charm of Vamana. Nammazhvar refers to Vamana as Kalvan, implying that His cleverness in deceiving Mahabali was amazing. Andal, in Her Nachiar Thirumozhi talking of the Lord making His entry, says, ‘adira pugutha.’ Adira would mean a shake. But what She is saying here is not that the earth shook at His approach. Parasara Bhatta had an interesting explanation. He said that it was a reference to Vamana, who had only been a giver. The Lord had never been a seeker. So, when He had to ask Mahabali for some land, He was not sure how to do it. Hence, He shook with anxiety!