Hindus and Jains celebrate Diwali at the same time, but for entirely different reasons.

Hindus celebrate the return of Lord Rama to Ayodhya after fighting the forces of evil. Jains celebrate the day Lord Mahavira departed from his earthly body, to attain moksha.

Mahavira attained moksha at midnight on Diwali day, after his final discourse - the Uttaradhyäyan.

Eighteen kings from North India were present at Mahavira's final discourse. They decided to keep the 'light of his knowledge' alive by lighting lamps, with the thought: "The light of intelligence (Vardhamana Mahavira) is gone. Let us make an illumination of material matter." For Jains, Dipavali (or Diwali), the festival of lights, has its origin in this act of the kings and, as such, is an occasion for remembering the teachings of Mahavira.

Jains rejoice over Lord Mahavira's moksha during Deep Diwali. Mahavira's physical death at the age of 72 is considered his final liberation from the world. It is a day to celebrate and a day to light the inner lamp of knowledge.