Viswamitra

Vishwamithra was a brahmarishi who showed to the world that a man of resolution can attain the impossible with perseverance. His life story is one of a great friend of the world, one whose devotion to duty was of the highest order. Born as Viswaratha, he went on to become a brave emperor. His greed for owning Shabale, the holy cow in sage Vashista's ashram, forced him into a mighty duel with the sage. Losing all his weapons, he swore to do severe tapas, become a Brahmarishi and attain the power to destroy Vashista. Vishwamithra took the challenge of sending Trishanku to heaven in his mortal body, something that Vashista and his sons had turned down. In fact, when Trishanku was hurtling down to earth after being denied entry into heaven, Vishwamithra stopped him in mid air and created an alternative heaven there itself for him. He was prepared to go to any length to attain the status of a Brahmarishi. The Aswini Devas advised him to overcome desire and anger in order to be successful.  Sage Vishwamithra saved the life of Shunashefa when he was going to be sacrificed to Lord Varuna in place of Rohitha, Harishchandra's son. As a result, Varuna invited him to swarga where he took Vashista's challenge to prove that even Harishchandra could not be truthful all the time. While he lost to Harishchandra(but was happy nevertheless),his loss of face to Vashista perturbed him a lot and his desire to become a Brahmarishi became stronger.  The string of defeats–at the hands of Vashista, Menaka, as well as in sending Trishanku to heaven or in desiring to own Shabale–only made him more resolute to bring his senses and mind under control. Devendra appeared before him and declared him to be a Maharshi. In order to become a Brahmarishi, he asked the sage to accept agnividya, which he did readily.  Vishwamithra took over Vashista's sorrow and saved him, one who had been his sworn enemy. He considered Vashista to be his guru. With the help of more concentration, more severe penance, he was able to control his breath. Evil thoughts left him and he attained Samadhi. Brahmadeva finally declared him a Brahmarishi. From then on, he became a model to the world. After a string of good deeds, he left for the Himalayas and sat in meditation at the end of which he attained the exalted position of being one of the Saptharishis. Vashista was very happy that God had revealed the Vedas and the Gayathri hymn to Viswamithra. In turn, Vishwamithra has become the guiding light to all righteous people by blessing them with the all powerful Gayathri manthra.