In a previous incarnation (Kurma Avathar) that AMRITHAM (nectar) was secured from the ocean of milk and the same was distributed among the Devas. The Asuras who gave equal co-operation in getting the nectar failed to get their share. The failure to obtain nectar and enjoy the advantages infuriated the Asuras, with the result a great war started between the Devas and Asuras. This was called the Deva-Asura War subsequently.
The demons (Asuras) were headed by BALI, son of Virochana and grandson of Prahlada. During the conflict the Devas conquered the Asuras. So Bali sought the advice of the preceptor of the Asuras, Sukracharya. The preceptor suggested a big sacrifice called the VISVAJIT Sacrifice. Bali performed the same and attacked the Devas (Suras) again. Now the Devas could not stand the onslaught of the Asuras. On the advice of their Guru BRIHASPATHI they evacuated their capital AMARAVATI and went away. Bali became the Lord of the heavens also.
This bad predicament to the Devas made their Mother ADITI, wife of the great Sage KAASYAPA, very sad and on the counsel of her husband she began propitiating Lord Vishnu. Maha Vishnu the compassionate, saw the discomfiture of the Devas and their Leader Indra. So as promised to Aditi, Maha Vishnu was born as the son of Sage Kaasyapa and Aditi. Lord Hari appeared with resplendent jewels and weapons but the next moment became a short stature Brahmin boy as Aditi and Kaasyapa were looking on. This was Vaamana or the Dwarf Brahmacharin.
Babhoova the naiva sa vaamano vatuhu.
(The asuras were no other than the cousins of the devas, for the asuras too were born to the same sage Kaasyapa, but to another wife named DITI. So the existence of family feud should be nothing new or surprising).
Just then Vaamana came to know that BALI CHAKRA-VARTI was performing the great Horse Sacrifice.
(A word about Bali is essential here. Bali was no other than the grandson of Prahlada. Bali's father was Virochana. Bali's great grandfather was Hiranyakasipu).
HIRANYAKASIPU - PRAHLADA - VIROCHANA - BALI
Bali the great grandson of Hiranyakasipu and the grandson of Prahlada, had imbibed the qualities of both Hiranyakasipu and Prahlada. He was a man of greed and adventurous spirit like his great grandfather. He had the qualities of extreme haughtiness, ego and pride mostly found in the Asuras (demons). He was as well, a Hari Baktha like his grandfather Prahlada. He had the sagacity and knowledge of the Vedas and sastras like the sages of old. He had the effulgence and certain divine qualities like the devas. He respected the sages, Brahmins and Vedic scholars. He was not at all cruel like Hiranyakasipu.
Only he wanted to become the permanent Indra (the king of the Devas). This alone became the important problem for Vaamana to deal with. He has come down from the highest Bliss as the son of Kaasyapa to save Indra and to grant him the status quo and free the devas from eternal subjugation.
It is mandatory according to our Dharmasastras that virtue gained by one has its reward and the individual has to enjoy it while vice accumulated by one has its own bad effects that is sufferings and one has got to suffer.
ANY INDIVIDUAL WILL HAVE TO UNDERGO THIS BECAUSE IN THE DHARMASASTRAS IT IS NOT THE NET RESULT OF THE GOOD AND BAD ACTS PUT TOGETHER THAT IS CONSIDERED, BUT THE DEBITS AND CREDITS ARE TAKEN IN TOTAL ISOLATION.
Accordingly the Divine Dwarf decided to reward Bali for his good qualities which were, in fact, in abundance. The only vice the Lord could find in Bali was his insatiable desire to occupy the throne of Indra as the Lord of the Paradise permanently. If this is allowed the purpose of his appearance on earth as the Dwarf son of Aditi and Kaasyapa would be lost.
The Lord decided the course of action and started with staff in one hand and a wooden gourd in the other for the place where Bali was performing the great sacrifice. Vamana entered the big sacrificial hall majestically.
Chathram sadandam sajalam kamandalum vivesa.....
He was received by the Brighus with due honour. Bali on seeing this dwarf-like Brahmin with such divine brightness ran down the dais and welcomed him. Said Bali, "Swamin I am greatly honoured by your presence at this hour. May I know how I can be useful to you?"
Swagatham the namasthubhyam Brahman kirn karavaamathe.
"I infer O! Brahmin lad, that you are seeking something from me land, gold, an excellent house, food and drink, take whatever you desire".
Vamana said, "Of you, the foremost of the bestower of boons, I ask a small strip of land three feet measured by my feet".
Padaani threeni daithyendra sammithaani padaamama.
Bali gave out a big laugh and said " O ! My young Brahma-charin! Why have you asked for such a trifling thing?"
Vamana replied, " O! Chakravarthy! Please know it that to receive a gift of what is barely necessary is no sin. That is what sastras say".
"My dear young anchorite, it is evident that you don't know your needs and my capacity" retorted Bali.
"Leave alone my needs, O! the king of the three worlds, tell me what your capacity is?" asked Vamana.
"I can bestow on you even a continent" replied Bali.
"Do you know, O! demon king, that one, not satisfied with three steps cannot be satisfied even with a continent or the whole world," was Vamana's reply.
"Think well and tell me if you would require anything more," asked the Demon.
"If you please, give me what I have asked for. With that much shall I have achieved my purpose. Please remember, only so much as is useful, is wealth".
Vitham yaavath prayojanam was the calm reply of the Dwarf Brahmacharin.
Bali prepared himself to give away the gift. Just then Sukracharya, the family preceptor intervened and whispered, "I warn you O! King! This young boy is not really what he looks. In reality he is Lord Naaraayana himself who has come here on some specific purpose. So beware".
Bali promptly replied, "Swamin! I have promised the gift and my word must be kept. I may lose my position and power but Im a descendant of Prahlada, cannot break my word".
Though warned in time by his family preceptor, the great soul, Bali had no idea to deviate from truth. As he turned he saw his wife VIDHYAAVALI in her most exquisite make up with rich dress and adornment, ready with a pitcher of gold full of water to wash the feet of the Dwarf Brahmin (Vamana). Bali himself washed the glorious feet of the Lord with delight and bore on his head that water which was capable of consecrating the whole universe.
The gift was made according to the injunctions of the sastras. (Thubhyam Aham Sampradade Na Mama).
That moment the Dwarf form grew in a surprising manner wherein Bali saw the whole universe. In that unimaginably huge form the Lord covered the whole earth with one foot and covered the heaven with the second foot.
Then the Lord said, "Demon, three feet of ground were gifted by you to me. With two strides I have covered the earth and the heaven. There is no place for the third. Hope your word will not prove a fraud".
"Lord, I am not afraid so much of hell as I shudder terribly of infamy. There cannot be any place for any fraud with the descendant of Prahlada. Lord, the place of Indra was given to me by you and now you have taken it back. When you give, Lord, you are supremely good, nor are You less when You withhold. Afflictions from your hand are blessings in disguise".
Pumsaam slaaghya thamam manye Danda marhattha maarpitham.
"O ! Eternal Lord, here I offer you my head. Deign to place your worshipful foot on my head to make good the third. "Saying so Bali bent his head. The Lord said, " BALI ! IT IS MY NATURE TO DEPRIVE ONE OF ALL HIS POSSESSIONS WHOM I WANT TO BLESS. YOU KNOW, WHEN ONE IS IN OPULENCE MAN BECOMES HAUGHTY, WITH THE RESULT HE INSULTS THE WORLD AND MYSELF TOO. Now that you have proved worthy of my blessings having conquered the invincible illusion (Maaya), I am pleased to send you to a place hard of access even to the Gods that is the SUTALA REGION, in the Nether worlds."
Just then appeared Prahlada and paid his obeisance to the Lord. The Lord addressed Prahlada thus:
"Prahlada, my child, welfare unto you. Go thou to the abode in the SUTALA and be happy with your grandson and others. You shall see me there for all time standing mace in hand".
Then the Lord disappeared.
Thus in this incarnation we see that the Lord is prepared even to beg and help his bakthas. The aims are to help Indra, his brother, to get back his lost position and also to give succour to his baktha Bali (unlike in the previous avatharas).
Another peculiar aspect is that the Lord appeared first as Vamana (the dwarf) but in the end he appeared as Tri-vikrama pervading the whole universe proving that HE is VAASUDEVA that is ALL IS IN HIM AND HE IS IN ALL (OMNIPRESENT).
Maha Bali alone was singularly lucky to see Sriman Narayana in two opposite statures as Vamana the Dwarf and Trivikrama the All-pervading.