Sri Krishna avathar is compleately Divine. In this avathar Lord Krishna gave Bhagavat Gita to mankind- a compilation that is a religious classic with profound phylosophical thoughts. Gita has taught many things to mankind - to lead a life of love, affection,devotion,duty to parents,duty to country etc.
Kamsa the king of Madhurapuri was a cruel ruler.He imprisoned his father and took over the reign. He got his sister Devaki( whom he loved very much) married to Vasudeva and was bringing them home when Yogamaya appeared in the sky and warned Kamsa that the eighth child of Devaki born with the astrologoical star "Rohini" would kill him. Immediately kamsa was very restless and consulted his friend Jarasanda and according to his advice imrpisoned both Devaki and Vasudeva.
When ever devaki gave birth to a child he would immediately kill the baby. Devaki and Vasudeva were very sad and prayed to God Vishnu. The God appeared before them and said "I will be born as your 8th child and I will kill Kamsa Do not worry and have peace of mind." Saying this the God disappeared.
In the mean time Sri vishnu ordered Aadhi-sesha his five-hooded snake to go into Devaki's womb to be the seveth child. But He said this child would in time be transfered to the womb of Rohini the first wife of Vasudeva and would be born as Balarama - another avathar of the God. God again ordered that Yokamaya Shakthi would be born as a girl child to Yasoda a lady in the Yadava Vamsha in Gokulam at the same time when Sri vishnu would be born as Lord Krishna to Devaki. When Devaki gave birth to Lord Krishna. God ordered Vasudeva to take the baby to Gokulam leave it with Yasoda and bring the female child born to Yasoda to the prison to be with Devaki.
By Gods instruction the jail gates were unlocked by themselves, the guards fell asleep and Vasudeva took the child to Gokulam as divinely ordered. Further the river Yamuna which was in spate parted to open a path for vasudeva to pass with the child on his head. It was raining also. A five-hooded snake opened its hood like an umbrella over the child to protect the child from the rain. He reached gokulam and exchanged the children and he came back to the jail with Yogamaya born as a female child. The doors closed and locked itself automatically.
All the gaurds woke up from deep slumber as soon as he left the child with devaki and the child began to cry. The guards immediately informed to Kamsa that a child was born to Devaki. Kamsa went to the jail and was surprised and confused to find that the eighth child was a baby girl. However he snached the baby and dashed it head against the jail wall. The baby rose up and appeared as Devi Yokamaya and said "Ho merciless king why are you trying to kill me ? The one to kill you is already born and is growing up somewere. You cannot escape from death." saying this Yogamaya disappeared.Kamsa felt very restless.
In the mean time grand celebrations were going on in Gokulam over the birth of Sri Krishna. Kamsa heard about this and sent his men to Gokulam to find out how many children were born with Rohini as their Nakshatra. They went to Gokulam and found that 25 such children were born and informed Kamsa accordingly.They also told him that grand celebrations were going on in one Nandan's house. Kamsa somehow felt very uncomfortable about the birth of Krishna to Nandan and Yasoda and tried various means to kill the child but did not succeed. In time Lord Krishna killed the cruel king
Nandan sent young Krishna to a hermit for 'gurukula-vasam' for his formal education. Krishna learnt all the sasthras and all the arts. On finishing his education he shifted to Dwaraka from Madhura. He distroyed all the evil forces and and established Dharma. Arjuna – one among the 'Pancha-pandavas' (the five brothers) was Krishna's very close friend.He helped them win the war with 'Kowrawas' - the evil 100.During the war between the 'Kowravas" and the 'Pandavas'.
Lord Krishna gave the message of Sri Bhagvat Gita to Arjuna and to the world. The Bhagavad-Gita describes to us how the aspirant to the heaven avoids bodily excesses and indulgence and practices abstinence to be harmonized with God and detaced from all desire for the fruit of action. When one attains this unity of mind he arrives at a perfect understanding with his fellow beings through sympathy and love , He is the supreme lord of spiritual experience who conveys those moments of celestial glory when man gets beyond the veil of the flesh and also indicates their true relation to the problems of daily existence.