PAKAL Malayālam word meaning Day. A story about the origin of day, night, dawn and dusk is contained in Viṣṇu Purāṇa. At the time of the great Deluge everything from gods down to the rocks lay submerged in Parabrahman (Supreme Being). Brahmā sat in meditation to initiate what he termed as Jagatsṛṣṭi, the four species of living beings like the devas, asuras, pitṛs and men. When the meditation proceeded, the Tamoguṇa in Brahmā became prominent and so first and foremost of all, the asuras were born from his waist. Then Brahmā discarded his Tamoguṇa and the manifestation of the discarded Tamoguṇa became Night. Brahmā sat again in meditation and from his face sprang out the devas, who were embodiments of sattvaguṇa. Brahmā discarded the sattvaguṇa and it then became Day. That is why asuras are powerful at night and devas by day. Then another manifestation with sattvaguṇa predominating sprang out from Brahmā and it was called Pitṛs. Brahmā discarded that also and it became Dusk. Brahmā sat again in meditation and then were born men who were a manifestation of Rajoguṇa. Brahmā discarded that also and it then became Dawn. That is why men are strong at dawn and the pitṛs strong at dusk. It is because of these that it is said that day, night, dawn and dusk are bodies of Brahmā. All the above four are an asylum of the three guṇas. Night is called Uṣā and day, Vyuṣṭi. Sandhyā (dusk) is the time between Uṣā and Vyuṣṭi. When the fierce and terrible Sandhyā commences, a set of ferocious demons called Mandehas desire to eat the Sun. A fight ensues then between the Sun and the demons and by a curse of Prajāpati the demons die daily though their bodies never perish. At that time the best of Brahmins with the sound of ‘OM’ vibrating recite the gāyatrī and throw water upwards. That water transforms itself into Vajrāyudha and burns to death the wicked demons. The first oblation to the sacrificial fire is performed reciting the mantra which begins with “Sūryojyotiḥ”. ‘OM’ is but Bhagavān Viṣṇu, lord of the Vedas with the lustre of Ṛk, Yajus and Sāma. The very utterance of the word ‘OM’ therefore, destroys the demons Mandehas.
[Chapter 8, Aṁśa 2, Chapter 5, Aṁśa 1, Viṣṇu Purāṇa] .