Narada Purana — Purva Bhaga, Shloka 41
Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
एकादशी कलामात्रा द्वादश्यां तु प्रतीयते । द्वादशी च त्रयोदश्यामस्ति चेत्सा परा स्मृता ॥ ४१ ॥
ekādaśī kalāmātrā dvādaśyāṃ tu pratīyate | dvādaśī ca trayodaśyāmasti cetsā parā smṛtā || 41 ||
Jika Ekādaśī hadir hanya secebis (kalā) dan disedari pada Dvādaśī, dan jika Dvādaśī itu sendiri berlanjutan hingga Trayodaśī, maka Dvādaśī tersebut diingati sebagai ‘Parā’—hari yang unggul dan penentu untuk amalan.
Sanatkumara (in instruction to Narada on vrata and tithi-determination)
Vrata: Ekādaśī (with Dvādaśī-parā determination)
Primary Rasa: shanta
Secondary Rasa: bhakti
FAQs
It safeguards the sanctity of Ekādaśī-vrata by insisting on correct tithi-determination; when Ekādaśī is only momentary and effectively falls on Dvādaśī, the tradition treats the extended Dvādaśī as the decisive ‘Parā’ day for proper observance.
Bhakti is expressed through disciplined vrata; the verse emphasizes that devotion is not merely sentiment but includes careful adherence to dharma—observing the vow on the correctly ascertained lunar day.
Vedāṅga Jyotiṣa (calendar/astronomical reckoning) is implied: recognizing fractional tithi presence (kalā), and deciding observance when Dvādaśī overlaps into Trayodaśī.