Manava Dharmashastra 3.37

3.37

pūrve vaṃśyā pitṛpitāmahādayaḥ | apare putrapautrādayaḥ | tān mocayatyenaso narakādiyātanābhya uddharati | brāhmena vivāhena ūḍhā tasyāṃ yo jātaḥ putraḥ sa sukṛtakṛtpuṇyakṛdyadi bhavati | pitṝnparalokagatān | pitṛśabdo'yaṃ pretaparyāyaḥ na hi putrādisantateranyathā pitṛvyapadeśasambhavaḥ | daśaśabdaḥ pratyekamabhisambadhyate pūrvāparaśabdābhyām | ekaviṃśakamiti nirdeśāt | arthavādaścāyam | tenānāgatānanutpannānkathaṃ mocayatīti na vācyam | pūrveṣāṃ tvapatyakṛtena śubhena śrāddhādinā bhavatyeva pāpānmokṣa iti śrāddhādhikāre kathayiṣyate | ato ‘daśāparānenasaḥ mocayatī'tyetaduktaṃ bhavati—'daśapuruṣā yasminkule'pāpā jāyanta' ityālambanam |

The son born of the wife married by the Brāhma form is a performer of righteous acts, absolves from sins ten Pitṛs on the ascending side and ten on the descending side of his family, as also himself as the twenty-first.—(37)

Medhātithi’s commentary (manubhāṣya):
‘Pitṛs on the ascending side,’ i.e., father, grandfather, and so forth.

‘Pitṛs on the descending side,’ i.e., son, grandson, and so forth.

These he ‘absolves from sins i.e., saves them from the sufferings of hell, etc.

Tbe son that is born of the girl married by the Brāhma form ‘is a performer of righteous acts,’—i.e., his deeds are virtuous.

‘Pitṛs’—those that have gone over to the other world. The term ‘pitṛ’ here stands for dead persons; in no other sense could the son and other descendants be spoken of as one’s ‘pitṛs.’

‘Ten’— this is construed with both ‘ascendants’ and ‘descendants;’ as is clear from the man himself being spoken of as ‘the twenty-first.’

This verse is a purely laudatory exaggeration. Hence the question need not be raised how the man can save from sin his descendants, who are not yet born. For ancestors, freedom from sin is actually brought about by the proper performance, by the son, of Śrāddha and other rites; this we shall explain under the section on ‘Śrāddha.’ All that the assertion that ‘he absolves from sins ten descendants’ means is that in his family ten lines of descendants are born sinless.—(37)

This verse is quoted in Vīramitrodaya (Saṃskāra, p. 863), where it explains ‘Brāhmaṇī’ as ‘the girl married in the Brāhma form;’ and adds that the term ‘pitṛn’ includes the son and other descendants also;—also in Parāśaramādhava (Ācāra, p. 487);—in Aparārka (p. 88), which explains ‘Sukṛta’ as ‘doing what is enjoined and avoiding what is forbidden’;—in Hemādri (Dāna, p. 683); and in Smṛticandrikā (Saṃskāra, p. 227).

Comparative notes by various authors
Gautama (4.29.33).—‘The good sons purify; the son born of a wife married by the Brāhma form purifies ten past and ten future generations, along with oneself.’

Viṣṇu (24.29).—‘The son of a wife married by the Brāhma form purifies twenty-one generations.’

Yājñavalkya (1.58).—‘The son horn of this marriage purifies twenty-one generations.’

Āśvalāyana-Gṛhyasūtra (16.1.1).—‘The son born thereof purifies twelve past and twelve future venerations on both sides.’

Śaunaka (Vīramitrodaya-Saṃskāra, p. 863).—‘When a girl has been given away in the Brāhma form of marriage, the son born of her purifies twelve past and twelve future generations both on his maternal and his paternal sides.’