Brahmaa's one of the 10 sons was Maharshi Mareechi; Mareechi's son was Kashyap Jee, Kashyap Jee had two sons from his wife Diti - Hiranyakashyap and Hiranyaaksh. Hiranyaaksh was killed by Varaah Avataar; and Hiranyakashyap was killed by Narasinh Bhagavaan. Hiranyakashyap had four sons - Hlaad, Sanhlaad, Prahlaad and Baashkal. Prahlaad had four sons named Aayushmaan, Shivi, Baashkal, and Virochan and Virochan had a son named Bali.

This Bali was a great devotee of Vishnu. Once he defeated Indra and took his kingdom, Swarg, and exiled all Devtaa from their kingdom. He wanted to live there permanently. Shukraachaarya Jee suggested him to perform 100 Yagya for that. So he started performing those Yagya. He had completed 99 Yagya and was going to complete the 100th one. Seeing this Indra etc Devtaa went to Vishnu to tell their saga. Vishnu assured them to help them. He told them that He would incarnate from Kashyap and Aditi and would save them.

On the other side Aditi, Devtaa's mother, was also very sad seeing the condition of her sons, so she worshipped Vishnu and Vishnu told her also that He would incarnate as her son and would save Devtaa from Asur. So After a while, a baby was born to Kashyap and Aditi and immediately grew to 52 (Baavan in Hindee, that is how he came to be known as Vaaman) finger tall boy. He assumed a form of a Braahman boy and came to Bali's door to ask for alms. Bali was in the process of finishing his 100th Yagya. If he had finished that Yagya, he would have been the King of Swarg Lok. So in the meantime Vaaman Bhagavaan arrived at his door and asked for alms.

While performing Yagya, Bali could not send anybody empty-handed, so he called the boy inside and asked him - "O Braahman boy, What do you want?" The boy said - "I need only three feet land to perform my daily activities." Bali was astounded to hear such a strange request. He asked Him to ask for wealth, animals, palaces etc but the boy was firm in His request. Bali got ready to read the Sankalp to give Him three step land, that his Guru Shukraachaarya warned him not to give this boy anything as the boy was none other than Vishnu, and He came there with the intention to cheat him.

But King Bali said - "I cannot send anyone empty-handed from my house. That is my vow. If it is Vishnu, I am very fortunate that I am giving something to Him who gives to everybody; and if He is not Vishnu, I have nothing to lose. In either case I win." So he read the Sankalp to give three feet land to the boy. Shukraachaarya got very sad hearing his reply, so as he poured the water from the pot, he blocked the way of water by sitting in its spout. When water didn't come out, the boy said - "Perhaps something is blocking the way of water." and He picked up a straw and inserted in the spout. That straw pierced Shukraachaarya's eye and he moved from there suffering with pain. The way was open, the water flowed and Bali completed his Sankalp.

As the Sankalp got completed, the boy changed himself to a huge being, so huge that His head touched the Swarg Lok. In one foot He measured Prithvi, in second foot He measured Swarg Lok and his body covered the sky. There was no other place to measure so He said to Bali - "You promised to give me three feet land, where should I keep my third foot?" Bali was surprised to see this, he was just standing, his eyes opened wide, looking at Vishnu's huge form, folding his hands.

He said - "Prabhu, I greet you. Please measure your third foot on my body." and he lay down on his stomach. Vishnu got very pleased with this. He said - "I am very pleased with you. Since you lay down on your stomach, I give you the kingdom of Sutal Lok. Now ask what else do you want to ask?" Bali bowed his head and said - "I wish only for your blessings. Please guard my city." Vishnu said - "So be it. You will be next Indra in next Manvantar, till then you live there in Sutal Lok worshipping me." and He went away.

Bali went away to Sutal Lok, Devtaa got their kingdom back, and Vishnu sent His Chakra to guard his city. Such a great donor was this Bali, that knowingly fully well that Vishnu Himself had come to regain Swarg Lok from him, he did not back out of his vow; and he indeed gave to whom who gives to everybody.