Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
अश्वयुक्छुक्लनवमी द्वादशी कार्त्तिके तथा तृतीया चैत्रमासस्य तथा भाद्रपदस्य च //
aśvayukchuklanavamī dvādaśī kārttike tathā tṛtīyā caitramāsasya tathā bhādrapadasya ca //
The ninth day of the bright fortnight in Aśvayuja, the twelfth day in Kārttika, and likewise the third day in the month of Caitra, and also (the third day) in Bhādrapada—these tithis are declared especially auspicious for religious observance.
This verse does not discuss Pralaya; it focuses on dharmic time-keeping—identifying specific lunar dates as especially auspicious for religious observances.
It guides kings and householders to align worship, vows, charity, and other meritorious acts with prescribed tithis, reflecting the Purāṇic principle that correct timing (kāla) strengthens dharma and ritual efficacy.
The verse is a ritual-calendar directive: it highlights specific tithis suitable for vrata and worship; by extension, such auspicious dates are often used for initiating consecrations (pratiṣṭhā) or other ceremonial undertakings.