Narada. Maharshis of Ancient India

Narada, Lord Brahma's son, was asked to leave Satyaloka, be born twice as a human being in order to understand the trials and tribulations of earthly life. So first, he was born as a gandharva when he invented the Veena. Second, he was born as a son of a housemaid who worked in a brahmin's house. Thus his mind was filled thoughts of God and service to Him. God appeared before him saying that he had fulfilled his purpose.
Soon after, there was the great deluge and everything was destroyed. When Brahma thought of creating the world all over again, Narada was born along with four Sanaka brothers and the Prajapathis. It is as a result of his brother's curse that he roams about the world, playing on his Veena, singing the praise of the Lord.  Narada blessed Dhruva when the latter resolved to go to Madhuvana and perform penance.
He beseeched Devendra to release Kayadhu( Hiranyakashipu's wife) when she was being dragged so that the child in her womb could be killed. Later, in the pious environs that Narada created for her, she gave birth to Prahlada. Upon the advice of Narada, Ratnakara who was the head of a band of robbers , went into a state of Samadhi chanting Lord Rama's name.  Sage Narada was instrumental in getting the Bhagvatha composed; he himself  was a Parama Bhagvatha.
He enlightened the people of the world  about the greatness of God, the need to love Him and be grateful to Him. Our Puranas proclaim that he was a child of the Goddess of Devotion. It's believed that he still roams  all over the world, unseen by the mortal eye, carrying out the Lord's biddings. Narada Bhaktisutra has become a beacon to spread bhaktirasa among those who want to reach the Creator.