In Hindu religion, transmigration is the passing of jiva (invidual) after death from one body to another. Every living being is a combination of sentient as well as non-sentient elements, known as atma and anatma, respectively. These two are poles apart in all respects. The sentient constituent of the living being is eternal, unchanging and true. Anatma is ephemeral, and is subject to six modifications, namely, existence, birth, growth, maturity, decay and death. As the body experiences modifications and disintegration, the indweller also seems to experience childhood, youth, and old age and finally passes on to another body. The self that transmigrates from one body into another retains its core identity.
This transmigration of soul depends much on the past actions of the self. As the body is the substratum for experiencing pleasure and pain, the Self acquires a temporary body, which is suitable for experiencing the results of his past deeds. The human body is acquired as a result of good deeds in the past. The good actions are the assets of a dying man journeying to the next life. Therefore, one should be mainly careful to do good work and avoid evil work, and also to practice meditation etc., so that only good thoughts follow the Self.
Meditation, work, and previous impressions follow the soul while entering into a new body. Human beings have the opportunity to make an effort to transcend this transmigratory cycle of birth and rebirth, as they can realize that they are caught in bondage, which leads to endless misery. By acquiring knowledge of the Self, one distinguishes himself from his body and realizes himself to be all pervading consciousness. On the other hand, whoever identifies himself with the insentient body gets entangled in the cycle of birth and death.
The liberating knowledge which puts an end to the transmigratory cycle is the knowledge of Brahman. It can be attained by sadhana and by the grace of Guru.