According to The Hinduism, 6 Major Reasons For Rebirth (Punarjanma)
According to the Hinduism, there are several reasons why the soul takes on different physical bodies or rebirths and it is an infinite cycle until and unless the soul gets the salvation which depends on the actions (Karma). Let's understand it what Sanatana Dharma says about it.
To experience the fruits of one's karma
This is the main reason for rebirth. A person's karmas influence his or her life and destiny. Sattvika karma i.e. good or righteous deeds, reward one with the pleasures of swarga (abode of the devas)."
Raajas karmas or pleasure-seeking material actions reward one with mrutyu-loka (mortal realm or earth). And tämas karma, actions related to inertia, laziness and evil, condemn one to patala-loka (the lowest realm or the nether world). When the jiva exhausts its sāttvika karmas in swarga, it gets a human birth on earth.
2. To satisfy one's desires
When a person indulges in material pleasures, he or she subsequently develops a stronger desire to enjoy more of it (vasana). This unending craving to satisfy one's desires causes the Jiva to assume new physical bodies.
3. To complete one's unfinished Sadhana
4. To fulfil a debt
When a Jiva is indebted to another Jiva, it gets a human birth to fulfil its debt and receive what is owed to it. The ma comes in the form of a relative, friend or an enemy.
5. To undergo sufferings because of a great soul's curse
A person's grave error or sin may incur the wrath or displeasure of God or a rishi. This results in the Soul of that person getting another birth, not necessarily into a human body.
6. To attain moksha
By the grace and compassion of God or a God-realized guru, a Jiva gets a human body to purge itself of the layers of base instincts or moral and spiritual weaknesses. When the Jiva takes on another body, it is God who gives it an appropriate one in keeping with its karmas. When the jiva enters the new body it does so with its subtle (Sukshma) and causal (Kaaran) bodies.
Sometimes the enlightened person (a Mukta) takes birth by God's wish to carry out a special mission.