Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
एकादश्यष्टमी षष्टी पौर्णमासी चतुर्द्दशी । अमावास्या तृतीया च ह्युपवासव्रतादिषु ॥ ३ ॥
ekādaśyaṣṭamī ṣaṣṭī paurṇamāsī caturddaśī | amāvāsyā tṛtīyā ca hyupavāsavratādiṣu || 3 ||
凡行斋戒、立誓(vrata)及诸般法行者,当取如是月日:一十一日(Ekādaśī)、八日(Aṣṭamī)、六日(Ṣaṣṭhī)、满月日(Paurṇamāsī)、十四日(Caturdaśī)、新月日(Amāvāsyā),并及三日(Tṛtīyā)。
Sanatkumara (teaching Narada)
Vrata: general upavāsa-vrata (fasting vows); includes Ekādaśī among recommended tithis
Primary Rasa: shanta
Secondary Rasa: bhakti
It identifies specific lunar days (tithis) traditionally regarded as especially fit for upavāsa (fasting) and vrata (religious vows), implying that disciplined observance on these days supports purification and dharmic merit.
By pointing to tithis like Ekādaśī and Paurṇamāsī commonly used for worship and restraint, the verse frames bhakti as practiced through regulated devotion—fasting, vow-keeping, and worship performed on sacred calendrical times.
It relies on calendrical discipline—tithi-based timing of rites—closely connected with Jyotiṣa (Vedāṅga astrology/astronomy) for determining the correct lunar day for vows and fasts.