Matsya Purana — Yayāti and His Sons: The Exchange of Youth and Old Age
सन्ति ते बहवः पुत्रा मत्तः प्रियतरा नृप जरां ग्रहीतुं धर्मज्ञ पुत्रमन्यं वृणीष्व वै //
santi te bahavaḥ putrā mattaḥ priyatarā nṛpa jarāṃ grahītuṃ dharmajña putramanyaṃ vṛṇīṣva vai //
O King, you have many sons dearer to you than I. Therefore, to take up the burden of old age—namely, the responsibility for your care and the kingdom—choose another son, one who is wise in dharma.
This verse does not address pralaya or cosmic dissolution; it focuses on royal household ethics and the practical-dharmic choice of a successor.
It emphasizes dharmic succession: a king should entrust responsibility (including care in old age and governance) to a son who is dharmajña—competent, righteous, and fit to uphold rajadharma.
No explicit vastu, temple-building, or ritual procedure appears here; the verse is ethical-political counsel about selecting a worthy heir.