Manava Dharmashastra 2.153

2.153

na ca vayasā svalpena bālo bhavati kiṃ tahyaṃjño mūrkho vṛddho'pi yaḥ | mantrada upalakṣaṇam | mantrānvedānyāṃ dadātyadhyāpayati vivṛṇoti ca sa pitā bhavati | vai śabda āgamāntarasūcakaḥ | devānāmadhyeva āgamaḥ purāṇa eva | tathā caitihyasūcakaḥ paropadeśa āām̐huriti | ajñaṃ mūrkha bāla ityāhuḥ smatpūrve'pi | piteti mantradam | itikaraṇaṃ svarūpaparatāṃ bodhayati | yataḥ parataḥ śrūyate | bāla ityetena śabdenājñamātraḥ | ataśca bālaśabdādvitīyāyā abhāvaḥ | chāndogye śaiśavaṃ brāhmaṇametadustutaḥ smṛtikāreṇa varṇitam |

The ignorant person is verily a “child,” while the imparted of mantras is the “father.” They have called the ignorant man “child,” and the imparter of mantras, “father.”—(153)

Medhātithi’s commentary (manubhāṣya):
It is not by reason of his younger age that one is known as ‘child’ it is the ‘ignorant’—uneducated person—who, even though old in age, is called ‘child.’

‘Importer of mantras’—is used figuratively; the sense being that ‘he who imparts,—i.e., teaches and expounds,—the Mantras—i.e., the Vedas—becomes the father.’

The particle ‘vai,’ ‘verily,’ indicates the support of other scriptures; and these scriptures (thus referred to) must have been regarded by the said gods as ancient and authoritative. Hence it is that we have the term ‘they have called.’ which points to a traditional belief.

‘The ignorant’—uneducated—‘person,’—‘they’—i.e., even the ancients—have called ‘child’; —and ‘the importer of mantras, the father.’ The particle ‘iti,’ occurring after the term ‘bāla,’ points to the exact form of the traditional belief;—the construction being—‘ajñam bāla iti etena śabdena āhuḥ,’ ‘the ignorant person they have called by the name child.’ It is on account of the presence of this ‘iti’ that the accusative ending is absent in the term ‘bāla.’

This story about the child (Āṅgirasa) occurs in the Chāndogya, and the author of the Smṛti (Manu) has reproduced it here only in sense.—(153)

This verse is quoted in Parāśaramādhava (Ācāra, p. 305)—in Vīramitrodaya (Saṃskāra, p. 480);—and in Smṛticandrikā (Saṃskāra, p. 93).

Comparative notes by various authors
(verse 150-154)
See Comparative notes for Verse 2.150.