Creating life did never mean the end of God’s responsibility. He is supposed to manage and protect his creation with his supernatural powers as he is well aware of the disorders to happen without proper management. To control these chaos and flow of life huddle less, he incarnates in every era when his creation faces degeneration.
In the Bhagvad Gita, 4/7-8, Sri Krishna says:
O people of Bharat, whenever there is degeneration of thought and an increase in sin, I shall incarnate in different forms… I will protect and support the honest and virtuous people, and destroy those who live in sin. I shall incarnate era after era to establish righteous thought.
Right from the inception of life, different Gods have incarnated 108 times. Out of those, Vishnu’s ten incarnations are significant in Hindu mythology. Those are:
Vishnu was incarnated on earth for the first time as a Matsya or fish to save life, when the judgment day arrived. He chose saint Manu Vaivasvat to help him in this noble job. He met Manu as a small fish and gradually grew large to warn him about the judgment day and requested him to collect all samples of living beings in a pair to establish life again on earth. He said Manu to board a ship which will be propelled by him. After the disaster, life was recreated by Manu.
The second incarnation was Kurma or kacchap or tortoise. He took this form to save Gods from disease and old age providing them immortality. He helped churning of the sea done by Gods and demons to find amrit by holding the mountain Mandar on his back.
The third incarnation was Barha or Boar. The twin sons of Kashyap and Diti, Hiranyaksh and Hiranyakashipu were rewarded with incredible power as boons by Brahma. Hiranyaksh took earth to the depths of the ocean. To revive the earth and kill him, Vishnu took this incarnation.
The fourth carnation of Vishnu was half-lion half-man – Narsimha. Infuriated by the death of his twin brother, Hiranyakashipu pleased Brahma to get a boon of almost immortality as he could not be killed by God, Man or Demon. Afterwards, he declared himself as the God. But his son Prahlad did not accept him as the God as he was a great devotee of Vishnu. So, Hiranyakashyapu tried to kill him. To save his devotee and mankind from the torture, Vishnu incarnated himself as half- lion-half- man to kill Hiranyakashyapu.
Vishnu was incarnated for the fifth time as a Vaman to save humanity from the tyranny of the demon king Bali. He took back the earth and heaven acquired by Bali, by putting his two feet on it. He also sent Bali to the Patal or the nether land.
Parshuram was the sixth incarnation of Vishnu. He took birth to control the over powered Kshyatriyas on the earth. He destroyed the Kshyatriyas 21 times from the earth. He is the only incarnation, who is believed still alive as he got the boon to remain immortal.
Ram is considered as the seventh incarnation of Vishnu. He was known as Maryada Purushottam or the Supreme Being with the highest moral conduct. He was born to kill the powerful demon Ravan.
The pivotal character of the Mahabharata, Krishna was the eighth incarnation of Vishnu. He was not armed to destroy sins, yet he did it through the Pandavas. He also killed his sinful maternal uncle Kansa.
Buddha was the ninth incarnation of Vishnu. He was born to impart knowledge of the real life and Mokshya or solace.
Vishnu’s tenth incarnation is believed to be the Kalki, who is yet to born.