It has been narrated in the Agni Purana that the man who practises the Nakta Vrata in the month of Margashirsha, goes to the region of Vishnu. The Vratas known as the Vrata of a single meal each day (Ekabhakta), the Dwadashi-Vrata, and the Tila-Vrata should be practised for four consecutive months.
Agni Purana states that by practising Vratas during the four months commencing from the month of Shravana, a man is able to witness the realisation of all his heart-felt desires. The resolution of practising the Chaturmashya Vratas spoken of before should be first solemnly made, by fasting on the day of the eleventh phase of the moon in the month of Ashada. The god Han, manifest as the sun god, should be worshipped under the auspices of the continuance of that luminary in the sign of cancer, and by reciting the prayer.
It has been stated that a Brahmana should abstain from taking all animal-food, forego the use of oils and unguents, and worship the god Hari for three days by observing a fast on each alternate day, whereby he would attain the region of Lord Vishnu. A man, by practising the vow of silence (Mouni-Vrata) and the one known as the Chandrayana, goes to the region of Vishnu and becomes an emancipated spirit in the end. Similarly, by practising the Vrata known as the Prajspaiya, while living on a diet of powdered wheat and barley, a man ascends the heaven after death. Again by drinking milk simply, or by living solely on the composition known as the Panchagavya or on roots and vegetables, a man goes to the region of Vishnu after death. Similarly the man who abstains from all meat, lives on a diet of barley, or foregoes the use of all sweet articles and attains the god Han.
The process of observing the Koumada Vrata has also been described in the Agni Purana. It is said that the Koumada Vrata should be practised in an empty stomach in the month of Ashvina. Lord Vishnu should be worshipped in the Vrata, occurring on the day of the twelfth phase of the moon's increase. Lotus and other water-flowers and Naividyas illuminated by lamps of oil or clarified butter, should be offered to the god. The god Vasudeva should be worshipped with garlands of Malati flowers, and by reciting the Mantra running as "Om obeisance to Vasudeva." And it has been said that thus by practising a fast for a month in connection therewith, a man acquires piety, worldly prosperity, wealth and salvation, in short, every thing he sets his mind upon.