Matsya Purana — Measures of Time: Caturyuga Computation
सप्तर्षीणां मनोश्चैव आदौ त्रेतायुगे ततः अबुद्धिपूर्वकं तेन सकृत्पूर्वकमेव च //
saptarṣīṇāṃ manoścaiva ādau tretāyuge tataḥ abuddhipūrvakaṃ tena sakṛtpūrvakameva ca //
In the beginning—and later in the Tretā Yuga as well—this account/practice concerning the Seven Sages and Manu was undertaken by him, first without full understanding, and then once again with deliberate intent.
Indirectly, it emphasizes continuity of sacred tradition across cosmic time (Yugas and Manu-lineage), a key Purāṇic idea that survives even across upheavals like Pralaya.
It highlights the shift from acting unknowingly to acting with clear intention—an ethical principle in the Matsya Purana: dharma should be performed with understanding and proper resolve, not merely by accident or imitation.
No direct Vāstu or iconography rule is stated; the ritual takeaway is about correct intentional performance (buddhi and saṅkalpa), which underlies proper execution of rites described elsewhere in the Matsya Purana.