Narada Purana — Purva Bhaga, Shloka 51
Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
संपूर्णैकादशी शुद्धा द्वादश्यां नास्ति किंचन । द्वादशी च त्रयोदशयामस्ति तत्र कथं भवेत् ॥ ५१ ॥
saṃpūrṇaikādaśī śuddhā dvādaśyāṃ nāsti kiṃcana | dvādaśī ca trayodaśayāmasti tatra kathaṃ bhavet || 51 ||
एकादशी पूर्ण व शुद्ध असून द्वादशीचा कणभरही स्पर्श नसताना, त्रयोदशीच्या यामात द्वादशी असेल—तर तेथे व्रतनिर्णय कसा करावा?
Sanatkumara (in dialogue with Narada)
Vrata: Ekādaśī-vrata
Primary Rasa: shanta
Secondary Rasa: vicara (inquisitive/reflective)
FAQs
It highlights that Ekādaśī-vrata is not merely fasting, but a dharmic discipline requiring purity of tithi; correct timing safeguards the sanctity of the vow offered to Viṣṇu.
By insisting on careful observance, it teaches that bhakti is expressed through attentive, rule-guided worship—honoring Viṣṇu with sincerity and precision rather than casual practice.
Vedāṅga Jyotiṣa (calendar/astronomical timekeeping): the verse raises a tithi-nirṇaya problem—when Dvādaśī is absent on its expected day but appears within Trayodaśī—prompting precise calculation for fasting and pāraṇa.