Matsya Purana — Yayāti and His Sons: The Exchange of Youth and Old Age
पूर्णे वर्षसहस्रे नु पुनर्दास्यामि यौवनम् तथैव प्रतिपत्स्यामि पाप्मानं जरया सह //
pūrṇe varṣasahasre nu punardāsyāmi yauvanam tathaiva pratipatsyāmi pāpmānaṃ jarayā saha //
When a full thousand years have passed, I shall grant youth again; and in the same manner I shall take upon myself the burden of sin, together with old age.
It reflects a Purāṇic theme within the Matsya narrative: divine control over time and conditions of embodied life—youth, decay, and moral burden—often framed around vast cycles (like a thousand years) that parallel cosmic rhythms associated with Pralaya accounts.
By linking aging and “sin-burden” (pāpa) with moral accountability, it reinforces that kings and householders must govern and live by dharma to reduce pāpa; the verse implies that worldly vitality is temporary and ethically conditioned, encouraging disciplined conduct and ritual duty.
No direct Vāstu or iconographic rule appears in this verse; its practical takeaway is ritual-ethical—purification and dharmic living to counter pāpa—rather than temple-building or town-planning instruction.