Diwali is the festival of lights celebrated every year on the propitious occasion of the return of Ram and Sita, in the story Ramayana. Legend has it that Lord Krishna after witnessing Sathyabhama killing Demon Narakasura took an oil bath to get rid of the blood spattered on his body. Another popular belief is that ritual cleansing of the body is to remove all dirt, evil and inauspicious things before the arrival of Goddess Lakshmi on the next day. A deeper spiritual meaning of Diwali comes from the fact that it is the darkest night of the year. So to squander the darkness of ignorance and hopelessness, people light diyas on Diwali.
On the previous night of Diwali people clean, renovate and decorate their homes. On the day of Diwali, members of the family dress up in new cloths to participate in family pooja and light up diyas inside and outside the houses to seek the blessings of goddess Lakshmi. The festival is celebrated with exchange of gifts between family members and close friends along with a family feast.
In South India, a convention of taking oil bath during Naraka Chathurdashi and Diwali. Symbolically oil bath imply new beginning by removing all the ego, birse, fights, self esteem and jealousy. In Abhyangasnan, the holy bath is a ritual that includes a full body massage. The specially prepared ayurvedic oil consists of sesame oil, jeera and pepper pods. Sesame oil is used because Diwali is celebrated during cold windy season which increases heat in the body and help to stay warm. Applying oil from head to toes not only moisturizes our skin but also removes environment pollutants, toxins, dead cells, relieves from stress and calms our mind, increases blood circulation, stimulates nerves and muscles there by strengthening them. Instead of soap we use gram flour with turmeric which also enhances the value of the bath. According to mythology early morning bath signifies the destruction of evil within us and as sacred as bathing in River Ganges.
Diwali, the festival of lights, the festival of rituals and the festival of different myths brings hope and prosperity in the life of every one with the blessing of Goddess Lakshmi.
Source:
http://www.hindu-blog.com
https://en.wikipedia.org
http://www.thehealthsite.com