King Gadhinandana decided to go on penance and went deep into the forest to pray. He meditated for years, living a life of austerity. Lord Shiva became pleased at his devotion and appeared before him to ask, ?Why are you praying to me since so long, subjecting yourself to all kinds of hardship? What do you want? I am worried about you.?
The king replied, ?I want to be as eminent as Sage Vashistha and be equal to him in all respect. I want to be able to use the Brahma-astra as he does.?
Shiva could not turn down his request and so granted him the boon.
King Gadhinandana, filled with pride at his newly acquired power, decided to destroy the sage and become all powerful. With his full army he advanced to the sage'shermitage and ordered his men to shoot him and all his disciples down. They shot and the arrows flew straight but on nearing the sage, the arrows got either twisted or cracked and fell to the ground. Unable to cause any harm to Sage Vashistha, the king took out his Brahma-astra and flung it with full force towards the sage, who sat deep in mediation. The astra went flying but fell near the sage'sfeet without causing him any harm. Lost and forlorn, the king approached the sage with tears in his eyes and begged, ?Sage Vashistha, do tell me what is it that makes you more powerful than me??
The sage laughed out aloud and replied, ?You are a Kshatriya whose job is to fight for the people and the kingdom. I am a Brahmin, whose job is to pray and conduct religious services for the benefit of mankind. You have done what is your job and I have done what is mine.?
The king interrupted, ?No, it is not possible. Our birth has nothing to do with this. I too prayed for long and that'swhy I was blessed by the Lord Himself.? Dissatisfied at the turn of events, the king again went deep into the forest and did penance for long.
Pleased at his devotion, the Lord appeared and told the king that henceforth the king would be known as Vishwamitra. The king asked, ?Will I be known as a rishi now??
The king replied, ?You will be known as rajarishi, kingly sage.?
The king, not satisfied, asked, ?Will I be known as Brahma-rishi like Sage Vashistha??
The Lord did not deign it fit to reply and disappeared.
Thus the king became known as Vishwamitra, the rishi of kings, but could not become equal to Sage Vashistha who was Brahma-rishi.