The Paryushan is the most important festival among the Jain festivals; and it is observed during every Chaturmas commencing on the twelfth day of the fortnight of the waning moon, in Bhadrapad and ending on the fourth day of the fortnight of the waxing moon in the Bhadrapad.
During these eight days, the entire Jain Society becomes spellbound in an atmosphere of enthusiasm and felicity. All Jains, the young and the old perform Atthai Tap – fasting for eight days at a time.
Some men and women; and even children take the vow of Paushadh Vrat also for eight days During these days, the spiritual preceptors read out and explain in detail the Kalpasutra, the most sacred scripture of the Jains.
All the members of the congregation listen to that explanation, overwhelmed with the emotion of devotion.
Seven days are days of attainment and the eighth day is one of fulfillment or achievement In this manner,the Samvatsari Mahaparva the annual festival is celebrated.
Listening to the holy voice of the spiritual preceptors when they explain the 1250 fundamental Sutras; performing the Samvatsarik Pratikraman, (the annual atonement) for seeking the forgiveness of those people whom one hates or against whom one nurses a grudge; forgetting all hatred and spite-these, constitute the Samvatsarik aradhana -the annual atonement.
Paryushana is the most important annual holy event for Jains and is usually celebrated in August or September in Hindi calendar Bhadrapad Month’s Shukla Paksha.
Jains increase their level of spiritual intensity often using fasting and prayer / meditation to help. The five main vows are emphasized during this time.