Bhishma is the the grand father of the Pandavas and Kauravas. In the previous story we read how Ganga who marries Shanthanu leaves all her new born children in the river and was stopped by Shanthanu when she is about to put her 8th child in the river. This eighth child was called Devwrath.
Today we will talk about why the children born to Ganga were put in the river. In the Celestial world ,the world where Gods live, there different classes of worshipers who are called by different names. In the present story there were 8 celestial beings who were known as Vasus. One day these eight Vasus were travelling with their wives and see the hermitage of the great sage Vasista.
In order to pay their respects, (though they were Celestial beings they used to respect sages who did great penance and had acquired great powers) they came to the heritage of Vasista. Sage Vasista had a beautiful cow whom Vasista loved a lot. One of the Vasu’s wife wanted to have the cow and forced the Vasus to steal the cow .
Vasista, who was then in penance saw what happened and after coming out of penance, cursed them to go to Earth as they have have behaved like human being by stealing the cow. Humans were considered very low compared to the Celestial beings. The Vasus immediately on knowing the curse of sage Vasista asked for his pardon and to withdraw the curse.
Vasista says he cannot draw back the curse once given and tells them that the moment they are born on Earth they can come back to the celestial world except the one who actually stole the cow. Vasista says that vasu will live for a long time on Earth attain lot of fame and will lead a princely life.
The Vasus then approach Ganga to bear them and give birth to them. In order to help them, Ganga marries Shaanthnu and bears the children and as soon as they are born she leaves them in the river to enable the Vasus to go back to Celestial world as promised by Vasista. The one Vasu who is left out on earth is known as Drvwrath who later becomes Bhishma.