The legend and life of Agastya is featured often in the Puranas and epics. In the Mahabharata, Indra advised Pandavas to use their years of exile wisely to travel, see new places, and learn new skills and to spend time with sages and learned people. This will help them in becoming better human beings and rulers. The story of upside down ancestors of Sage Agastya and their rebirth was heard by the Pandavas during their exile period.
Rishi Agastya had constant bad dreams about his ancestors. In every dream, they appeared hung upside down over a bottomless pit, crying that they would never be able to escape this miserable state unless they were reborn.
For this, they told Agastya, they needed him, their descendant, to marry and produce children. Heeding their advice, Agastya married the princess Lopamudra of Vidarbha kingdom.
She served Agastya with devotion and sincerity. But when they decided to have a child, Lopamudra wished that the sage should earn sufficient wealth for them to live in comfort. The sage decided that he could seek wealth from kings. But he was also particular that what he received as gift from anyone should not cause any loss or injury to others.
Sage soon realized that most kings did not have any proper wealth that could be gifted to him. Noticing that there was only nil balance in the account statements, Agastya told the kings that if he accepted any gift from them it would be a burden on the citizens.
But finally he did come across a king who wisely ruled the kingdom and had profit without over taxing his subjects.
Sage Agastya then had children with Lopamudra. Thus Sage Agastya repaid his debt to his ancestors and helped them be reborn so that they can use the birth to escape from the cycle of birth and death and attain moksha.