Shivapurana 7.2.17.19

Śivapurāṇa (complete text) 7.2.17.19

hutvā śiṣyasya taccheṣaṃ bhoktuṃ samupakalpayet |
tarpaṇāntaṃ ca mantrāṇāṃ kṛtvā karma yathā purā ||