Tithi-vicara
Determination of Tithi for Fasts, Parana, and Pitri Rites
श्वहतं पंचगव्यं च दशम्या दूषितां त्यजेत् । एकादशीं द्विजश्रेष्ठाः पक्षयोरुभयोरपि ॥ ३९ ॥
śvahataṃ paṃcagavyaṃ ca daśamyā dūṣitāṃ tyajet | ekādaśīṃ dvijaśreṣṭhāḥ pakṣayorubhayorapi || 39 ||
Si le pañcagavya a été altéré ou souillé, qu’on le rejette ; de même, ô meilleurs des deux-fois-nés, il faut abandonner une Ekādaśī entachée par la Daśamī, que ce soit dans la quinzaine claire ou dans la quinzaine sombre.
Sanatkumara (teaching Narada)
Vrata: Ekādaśī
Primary Rasa: shanta
Secondary Rasa: bhayanaka
It stresses ritual and calendrical purity: a vow (vrata) yields its intended spiritual fruit only when performed on a properly qualified Ekādaśī, free from taint (dūṣaṇa/vedha) by the preceding tithi.
By instructing devotees to observe Ekādaśī correctly, it protects the integrity of Viṣṇu-oriented vrata practice—showing that bhakti is expressed not only by sentiment but also by disciplined, rule-based observance.
Vedāṅga Jyotiṣa (lunar-day/tithi determination): it points to tithi-qualification rules such as Daśamī contamination of Ekādaśī (daśamī-vedha), applicable in both fortnights.