Antyeṣṭi Sanskara (अन्त्येष्टि)– The Last Ritual, is to pay tribute to the departed soul following to sacred tradition in Hindu Scriptures. There are altogether sixteen samskara (rituals) performed in Hinduism. Starting from the Garbhadhan which is performed at the conception for the purpose of conceiving a child as the first samskara, to the last which is called as Antyeshti samskara. After Antyeshti is completed, it is considered that Atma is permanently separated from the deceased body and has left the physical world. There is a close bonding between the Atma (soul) and the body all over the life. Once the physical body has served its purpose and is unable to sustain life further, the Jiva (soul) has to give up the current form of the body and has to move to the next form of life. The next form is as per his Karma.
Cremation is the most common method of funeral ceremony performed in Hinduism. However, certain groups and castes do not cremate in Hinduism. They bury the physical body. Ascetics and children are also generally buried or floated in the running water.
In Hinduism the body and soul are two separate entities. The ancient scriptures says- the soul once it is separated from the deceased body it is reluctant to leave the body, since it has desire and is attached with the corpse. The soul is very broken to see all his family and friends in pain and agony. Soul do not want to leave the physical body. It has a connection with the world through the body it has known so long. Once the cremation of the deceased body is fulfilled, in which Agni Sanskara is performed it cuts off atma feeling and attachment with the physical body.
In Hinduism, everything in the universe including the human body is made of basic five elements. These five elements (called as Panchtatva) connotes the elements i.e. Sky (Akash), Wind (Vayu), Fire (Agni), Water (Jal) and Earth (Prithvi). The Agni (Fire) which is the last rite is the passage of returning the body back to the five elements to its origin.
In cremation, the family and friends take the deceased body to the cremation ground. The cremation ground, which should be purified and the fire is lit with 100 kgs of wood, ghee(cow clarified butter) and body. Mantras are recited and the body is offered to fire. This is the final purification rite of the physical body. And the body is reduced to its five elements. Also post death rituals, the surviving family makes donations to charity on the deceased’s behalf, which also helps to give peace to the soul.
The roots of this sanskara are also found in Vedas. Rigveda says-
Burn him not up, nor quite consume him, Agni: let not his body or his skin be scattered,
O all possessing Fire, when thou hast matured him, then send him on his way unto the Fathers.
When thou hast made him ready, all possessing Fire, then do thou give him over to the Fathers,
When he attains unto the life that waits him, he shall become subject to the will of gods.
The Sun receives thine eye, the Wind thy Prana (life-principle, breathe); go, to earth or heaven.
Go, if it be thy lot, unto the waters; go, make thine home in plants with all thy members.
— Rigveda 10.16[11]
Funeral ceremonies are also described in detail in other scriptures, like Atharvaveda, In the Arnayaka of Krishna Yajurveda and later Sutras as well.
After the soul leaves the body it maintains some connection with the existing physical world. This period is around 13 days. The family also maintained a very close connection with the deceased during this period and recalls the person. All the final ceremonies related with cremation and mourning are performed during this period. The ceremonies help to maintain the separation of both deceased between the family and the deceased.
For these 13 days, Hindus recite the Garuda Purana with the other prayers to help the soul get departed and reach its final destination. It is believed when the Aatma leaves the body it adopts another spiritual form which is a subtle body and grows slowly day by day. The tenth day after the death, the interim spiritual soul grows completely and the family of the deceased offers the Pindas (food balls made of rice and water) for the development of Jivas for the next life. During this period the soul is called as pret on which one is departed from the physical world and not reached to next.
On the eleventh day the prayers are performed for the soul to reach in witness of God Vishnu and Yama(God Of death). On twelve and thirteen day the soul reaches to the next world and resides with the forefather called Pitra (ancestors). And the Antyeṣṭi is considered as completed. Every year the family performs the ritual in a specific month called Sharaad as the symbol of remembrance and respect of ancestors for the deceased.
In the end the truth is- anyone who is born will die and only karma goes with the soul..
Vedas and Upanishads 