" Yada yadahi dharmasya , glanir bhawati bharata , Abhythhanam adharmasya ,tadatmanam srijamyaham,"
-Shree Krishna
Krishna lived in Vrindavan as a cowherd and a playful, most enchanting flutist , a thief and the beloved of all the gopis and people of Vrindavan . But , his life purpose was grand and destiny had different plans .
He thus left Vrindavan to Kill his maternal uncle Kansa and to rescue his real mother and father , Devaki and Vasudeva from the jail of Kansa. After leaving Vrindavan, Bhagwaan Sri Krishna never returned back to Vrindavan except single time for meeting his parent Vasudeva Devki and Nand Baba -Yasoda for his final trip to his Param Dham Vaikuntha( this point is still disputed and contradicted by scholars).
After killing Kansa , Maharaja Ugrasen was crowned as the king of Mathura. Both Krishna and Balrama decided to stay at Mathura for a few days, and then they were sent to Ujjain , to the ashram of guru Sandipani .There Lord mastered the 64 kalaas in 64 days.
After completing their stay at the ashram , and gaining all the Vedic knowledge ,both the brothers returned to Mathura . But during this time ,Jarasandha , the king of Magadha , began to invade Mathura with his mighty army , his main aim was to annihilate the whole clan of Yaduvanshis.Jarasandha was defeated by Shree Krishna many times , but one time Krishna had to flee away from his attack[Read this story here].
So, Lord Sri krishna, aiming to safeguard his subjects from the invasion of Jarasandh, he took the all subjects of Mathura to Dwarka, while, they were asleep at night. People of Mathura could not know anything more, because, when they awaken next morning, they saw themselves near ocean with their houses also.
Bhagwaan Sri Krishna -Balram settled there and Sri Krishna became the Dwarkadhish and began to rule properly. These circumstances knowingly or unknowingly turned Krishna into a ruler from a cowboy , and a joyful flutist. After Krishna became Dwarikadhish , he became the protector of his people .The people of Dwarika began to worship him as their Lord and the protector from all difficulties. Krishna realised that his life was filled with responsibilities and once he returned to Vrindavan he would not be able to release himself from the unconditional love of Vrindavanvasis, his maa Yashoda ,Nandbaba , and specially the awaiting eyes of Radha.
So,Krishna accepted the destiny of his life and never returned Vrindavan , although once he sent Uddhav to teach Gopis, who were in deep pain due to separation from Krishna, the principles of yoga,,so that they could get freed from the moh of ‘ Shree Krishna’ and move on in their life.But this was in vain as the Gopis declared that their love for Kanha is the greatest form of Yoga and no other Yoga is supreme to it.. The love of Gopis , Radha ,Yashoda, Nandbaba for Krishna was unconditional , immense and changeless.
Radhe Radhe !!