Narada Purana — Purva Bhaga, Shloka 20
Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
स्नानदानजपादीनां कुर्वतामक्षय फलम् । तत्र कर्कटको ज्ञेयो दक्षिणायनसंक्रमः ॥ २० ॥
snānadānajapādīnāṃ kurvatāmakṣaya phalam | tatra karkaṭako jñeyo dakṣiṇāyanasaṃkramaḥ || 20 ||
沐浴、布施（ダーナ）、ジャパなどの行を修する者にとって、その果報は尽きることなく不滅となる。ここに知るべきは、太陽がカルカタカ（蟹宮）に入ることこそ、ダクシナーヤナ・サンクラーンティ、すなわち太陽が南行へ転ずる移り目である。
Sanatkumara (in dialogue with Narada)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: bhakti
FAQs
It teaches that performing core dharmic acts—snāna, dāna, and japa—at the Dakṣiṇāyana transition yields akṣaya (inexhaustible) merit, highlighting saṃkrānti as a spiritually potent time.
While framed as ritual timing, the verse supports bhakti in practice by directing devotees to intensify japa and charity on sacred calendrical thresholds, making devotion steady and fruitful.
Jyotiṣa (Vedāṅga astrology/astronomy): it identifies Dakṣiṇāyana-saṃkrānti specifically with the Sun’s ingress into Karkaṭa (Cancer), linking calendrical astronomy to ritual efficacy.