Narada Purana — Purva Bhaga, Shloka 27
Śrāddha-prayoga: Niyama, Brāhmaṇa-parīkṣā, Kutapa-kāla, Tithi-nyāya, and Vaiṣṇava-phala
क्षयाहस्य तिथिर्या तु ह्यपराह्णद्वये यदि । पूर्वा क्षये तु कर्त्तव्या वृद्वौ कार्या तथोत्तरा ॥ २७ ॥
kṣayāhasya tithiryā tu hyaparāhṇadvaye yadi | pūrvā kṣaye tu karttavyā vṛdvau kāryā tathottarā || 27 ||
க்ஷய நாளில் தொடர்புடைய திதி இரு அபராஹ்ணங்களிலும் நீள்ந்தால், க்ஷயத்தில் முன்திதியிலே கர்மம் செய்ய வேண்டும்; வ்ருத்தியில் பின்திதியிலே செய்ய வேண்டும்.
Sanatkumara (teaching Narada the technical rules of tithi and ritual timing)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: none
FAQs
It protects the integrity (śuddhi) of vrata and pūjā by teaching correct tithi-nirṇaya, ensuring devotion is offered at the scripturally intended time rather than by guesswork.
Bhakti is expressed through disciplined observance; by aligning worship with the correct tithi (even during kṣaya/vṛddhi anomalies), the devotee’s intention and practice remain faithful to dharma.
Vedāṅga Jyotiṣa—specifically, the rule for deciding whether the earlier or later tithi governs an observance when a tithi is lost (kṣaya) or extended (vṛddhi), using aparāhṇa as the deciding window.