Manava Dharmashastra 3.136

3.136

kaścinmanyeta pitṛkṛtye trīnityuktam | pūrvaśloke ca nānāśākhādhyāyina upāttāḥ | tatra saṃbrahmacāriṇāṃ nāsti prāptiriti tadāśaṅkānivṛttyarthamidam | eṣāṃ trayāṇāṃ traividyānāmanyatamo bhojanīyaḥ | etaduktaṃ bhavati—samānaśākhādhyāyino nānāśākhādhyāyino vā bhojanīyāḥ | arcitaḥ pūjitaḥ prārthita arghādinā | sāptapauruṣī tṛptiḥ | saptapuruṣānvyāpnoti | anuśatikāderākṛtigaṇatvādubhayapadavṛddhiḥ | kālamahatvopalakṣaṇārthaṃ caitat | dīrghakālā pitṝṇāṃ tṛptirbhavati | yāvatsaptapuruṣā āgāminaḥ putrapautrādayo jātā janiṣyante vā tāvattathāvidhabrāhmaṇadānāt pitarastṛpyanti | śāśvatī nāntarā vicchidya punarudbhavati, kiṃ puna: sarvadā sthitaiva |

If any one of these should dine, duly honoured, at the Śrāddha performed by a certain person, there would be ever-lasting satisfaction for his ancestors, lasting till the seventh degree (of descendants).—(146)

Medhātithi’s commentary (manubhāṣya):
Some people might argue as follows:—“It has been asserted that ‘at the rite performed in honour of ancestors one should feed three Brāhmaṇas;’ and in the preceding verse the learners of several recensional texts have been mentioned; so that there is no possibility of one’s own companions in study being fed.”

And it is with a view to set aside this notion that the author puts forward the present verse.

Of these three—the adherents of the three Vedas—anyone may be fed.

That is to say, one may feed either persons professing the same recensional text as oneself or those professing other several texts.

‘Duly honoured’—worshipped, approached, with offerings of water, etc.

‘Satisfaction to the seventh degree’—i.e., the satisfaction continues till the seventh degree of descendants. The prolonging of both vowels in the term ‘sāptapauruṣī’ is in accordance with Pāṇini 7.3.20. This epithet has been added for the purpose of indicating great length of time; the meaning being that ‘the satisfaction of the ancestors lasts for a long time.’ The meaning is that ‘by the feeding of the said Brāhmaṇa, the satisfaction secured to the ancestors is such as lasts till such time as his sons and grandsons to the seventh degree are born.’

‘Everlasting,’—i.e., it does not cease, and then appears again; it remains there always.—(146)