Speaking Tree: Mahalaya Amavasya & Navaratri: Legend of Karna
Three preceding generations of departed souls are believed to reside in Pitriloka, a realm between heaven and earth, governed by Yama, the god of death. In a thanksgiving gesture, Hindus propitiate their ancestors during the Mahalaya Paksha fortnight of the waning moon when ancestral spirits leave their abode to reside in their descendants' homes. The concluding day, the moonless night immediately before Navaratri, is the Mahalaya Amavasya. Feeding the hungry is considered the highest charity, in memory of one's ancestors so that they are not hungry in their life after death.
Karna, the legendary philanthropist of the Mahabharata, donated great wealth when he was alive. Once he died the charity he had done on earth was returned to him a thousandfold in Heaven. But, it was all gold and silver; there was no food. Karna's soul was hungry. When he asked for food, he was served gold.
He asked Yama the reason for not being served food and was told that he could be given only what had been donated by him or his descendants in his name. Karna's sons had all been killed in the war. There was no one to perform charity in his memory. Furthermore, Karna had only donated gold throughout his life. He had never donated food particularly in memory of his ancestors.
Karna replied that since he was unaware of his ancestors, he had never donated anything in their memory. He prayed to Yama to send him back to earth to make up for this deficiency. Yama agreed and restored him to life. For 14 days, Karna fed the poor, and offered oblations of water. On his return to the higher regions, he had food in plenty. These 14 days are commemorated as Mahalaya Paksha.
Yama also ordained that offerings one made on these 14 days would benefit all departed souls whether they were related to the donor or not. On the final day, Mahalaya Amavasya, food, obsequies and oblations are offered to all departed souls.