Pitris

The Pitṛs are the order of ancestors who dwell in Pitṛloka after death and who are satisfied by śrāddha, tarpaṇa and the offering of piṇḍa; in Vedic religion the debt to the ancestors stands with the debts to the gods and the seers as one of three, discharged by begetting offspring and by the funerary rites. At SB 2.3.8 the injunction 'tantuṁ tanvan pitṝn yajet' directs one who would extend the thread of his line to worship the ancestors — a direct reflection of that doctrine of debt.

Śrīmad Bhāgavata Mahāpurāṇa 2.3.8 — Sanskrit Wikisource (pinned oldid=201379)