Diwali, like its predecessor Durga Puja, Dussehra or Pongal, is not really a single festival, but consists of a succession of celebrations extending over a number of days; but, unlike Dussehra, the Diwali celebrations are different in form and bear different names from day to day.
The order of the Diwali series is as follows Narak Chaturdashi, Diwali proper, Jamghat and Bhratri Dwitiya. The Dussehra obervances are all grouped round a common centre, whereas those of the Diwali shift their point of convergence from one to another object of worship or veneration, and are members of one series only in so far as they follow one another in quick succession in the same week. The Dussehra is properly a festival of the Kshatriyas or the warrior caste; the Diwali is strictly a festival of the Vaishyas or the trading classes.
The Dussehra is, or at least was originally, a rural festival, connected with the cutting of the harvest; the Diwali was primarily an urban festival, for the obvious reason that the mercantile classes have always constituted the bulk of city populations. But there are. a few marked points of resemblance between these two festivals, due probably to their intrinsic importance. As in the Dussehra so in the Diwali, a mixed variety of social customs and observances have clustered round the chief religious ceremony of the season, and in both cases the religious growths have been overborne by the weight of parasitical forms, entieely unconnected with religion. The Diwali has again, like the Dussehra, assumed a dual aspect; for as in the Dussehra we have the worship of Durga and the performance of the Ram Lila taking place side by side, so in the Diwali, the worship of Kali and the worship of Lakshmi are held simultaneously on the same night, though not perhaps under the same roof.
The Diwali season commences on the fourteenth day of the dark fortnight of Karthik (October-November), this fourteenth day being called Narak Chaturdashi, because it commemorates the victory of Krishna over the demon Narakasura. The legend of Narakasura is contained in the Bhagavata Purana, the Kalika Purana and other mythologies of the same period.
According to these, Narakasura was a fearful demon dwelling in the country called Pragjyotisha, which some authorities identify with the western portion of modern Assam. This demon carried off the ear-rings of Aditi, the mother of the gods. The gods thereupon declared war against the demon but were unable to make a stand against him, and so they appealed to Krishna for help. Krishna fought with the demon, slew him, and brought back the stolen jewels in triumph.
According to another version, which is more popular, Narakasura carried off the daughter of Vishwakarma, the architect of the gods, and insulted her. The demon had been a notorious kidnapper of girls, and he had been in the habit of seizing and carrying off any beautiful damsel that caught his fancy. In this way he had made for himself a prodigious harem of sixteen thousand mistresses. And now he began to cast profligate eyes on the daughters of the gods themselves. Nothing daunted the intrepid voluptuary; maidens, princesses, nymphs, goddesses were alike in dread of him. The women of both the upper and nether worlds, therefore, joined together in supplicating Vishnu to destroy the demon and restore the sanctity of female honour.
But Narakasura, with all his weakness for the fair sex, was a demon of great piety and had, by penance and meditation, accumulated such a rich store of spiritual merit that Vishnu was for a time not only unwilling but actually powerless to do him harm. But when the load of daily sins outweighed his previous store of virtue, Vishnu gave leave to Krishna to march upon his stronghold and put him to death. But since spiritual merit, once earned, can never be totally blotted out by any subsequent acts of sin, Narakasura was allowed to crave a boon at the moment of death, and the boon he asked for was that tho day of his death might ever be commemorated as a day of feasting in the world.
“Be it so,” said Krishna, and then with one blow of his sword he made an end of Narakasura and liberated his sixteen thousand imprisoned mistresses in one moment. Such is the legend of Naraka Chaturdashi, which is also called Bhoot Chaturdashi, probably through a confused association of the popular meanings of ‘Narak’ (‘hell’) and ‘Bhoot’ (‘devil’). Another explanation is that the name Bhoot Chaturdashi alludes to the darkness of the night, a bhoot or devil being popularly believed to have a pitch-black complexion.