Uddhava (also known as Pavanayadhi) is a character from the Puranic texts of Hinduism, who is the friend and counsellor of Krishna the Avatar. He plays a significant role in the Bhagavata Purana, being taught the processes of yoga and bhakti directly by Krishna. The principle of these discussions is often referred to as the Uddhava Gita, similarly to the Bhagavad Gita wherein Krishna instructs Arjuna. According to some texts Uddhava was also Krishna's cousin, being the son of Devabhaga, who was the brother of Vasudeva, Krishna's father. His physical appearance was so like that of Krishna's that in some instances he is temporarily mistaken for the latter.
Message to Vrindavan 
In the Bhagavata Purana, after Krishna had defeated Kamsa, Uddhava came to see him, much to Krishna's pleasure. Krishna then requested Uddhava to visit Vrindavan with a message on his behalf to the Gopis and other residents of the village, who were missing his company. The content of the message and the feelings aroused by it when heard by the residents of Vrindavan constitute the highest understanding of love of God in the tradition of Gaudiya Vaishnavism.
Uddhava Gita 
Krishna spoke the Uddhava Gita (also referred to as Hamsa Gita) to Uddhava shortly before he left the world in order to help console Uddhava after his forthcoming departure. It commences with Uddhava's perplexity after he saw the impending destruction of the Yadava community, in which Krishna was also brought up, born as a Kshatriya.
Uddhava was famous as devotee and a dear friend of Krishna but even he could not fathom why he had not prevented the destruction from happening. Brahma, the creator, and the celestials implored Krishna to return to his divine abode after the purpose of his descent was over.
Krishna then explained why the Yadavas had to be finished, "Made insolent by prowess, heroism and fortune, and inclined to take possession of the whole world, this celebrated race of Yadu has been kept in check by Me as the ocean by its shore. If I depart (from this world) without destroying the huge race of the Yadus, who have grown insolent the entire humanity will meet its destruction..." Greatly saddened by this Uddhava approached Krishna and beseeched him to take him also. In reply Krishna then expounds the Uddhava Gita.
See also 
- Krishna instructs Uddhava (vedabase.com)
- The Uddhava Gita (Hindu.com)
- Krishna Explains the Yoga System to Sri Uddhava (srimadbhagavatam.com)
- Gita/Swami Guruparanada