Matsya Purana — The Episode of Madhu and Kaiṭabha: Gunas
*मधुकैटभावूचतुः यस्मिन्न कश्चिन्मृतवान् देव तस्मिन्प्रभो वधम् तमिच्छावो वधश्चैव त्वत्तो नो ऽस्तु महाव्रत //
*madhukaiṭabhāvūcatuḥ yasminna kaścinmṛtavān deva tasminprabho vadham tamicchāvo vadhaścaiva tvatto no 'stu mahāvrata //
Madhu and Kaiṭabha said: “O God, in that place where no one has ever died—O Lord—there we desire our slaying. Let our death indeed come from you alone, O great-vowed One.”
It reflects a pralaya-era mythic setting where ordinary cosmic order (including death and stable “places”) is disrupted; the asuras attempt to exploit an exceptional condition—“a place where none has died”—to control the terms of their end.
Indirectly, it illustrates a dharmic principle: even powerful beings try to secure immunity through technical conditions, but righteous authority ultimately prevails; for kings, it warns against loophole-driven injustice and emphasizes decisive, legitimate enforcement of order.
No direct Vastu or ritual procedure is taught in this verse; its key takeaway is conceptual—“place” (deśa) can be made a condition in vows/boons, a motif later echoed in Purāṇic ritual logic where time, place, and eligibility determine outcomes.