Manava Dharmashastra 6.2

6.2

yaduktaṃ tyaktaviṣayopabhogagandho'dhikriyata iti tadeva darśayati | valī tvakśaithilyam | palitaṃ keśapāṇḍuryam | apatyasyāpatyaṃ putrasya putra ityāhuḥ | satyapi duhiturapatye dauhitre putrasyāpi kanyāyāṃ jātāyāṃ naivaṃ vidhimicchanti śiṣṭāḥ | anye tu śiraḥpālityaṃ pautrotpattiṃ ca vayoviśeṣalakṣaṇārthamāhuḥ | yasya kathaṃcitpālityaṃ na bhavetso'pi vārdhakye vanaṃ samāśrayet | yathaiva 'jātaputraḥ kṛṣṇakeśastu' ādhāne'dhikriyate, evaṃ jātapautraḥ palitaśirāḥ | tatrāpi putrajanma kṛṣṇakeśatā ca vayoviśeṣopalakṣaṇārthameva | 'nātiśīghraṃ nāticiram' ityarthasyopalakṣaṇatve tu pramāṇaṃ vaktavyam |

When the householder notices his wrinkles and greyness, and sees his child’s child,—then he should r etire to the forest,—(2).

Medhātithi’s commentary (manubhāṣya):
It has been said before that the person who is entitled to the life of the Hermit is only one who has abandoned all longing for the objects of sense: and this is what the author is explaining now.

‘Wrinkles’—Looseness of skin.

‘Greyness’—the whiteness of the hair.

‘Child’s child.’—They explain this to mean ‘son’s son And cultured people have held that this rule does not apply if the man has only a son born to his daughter, or a daughter born to his son.

Others however have taken the ‘greyness of hair’ and ‘birth of the grandchild’ only as indicative of old age. So that even if an old man’s hairs may not, for some reason, become grey, he should, at the approach of old age, retire to the forest. Just as the person who has got a son and has his hairs still block is entitled to the ‘kindling of fire so is the man who has got a grandson and has his head turned grey entitled to the Hermit’s life. And in the former case also ‘the birth of the son’ end ‘blackness of hair’ are only indicative of a certain age.

Some people have taken the text to mean that ‘one should retire into the forest neither too early nor too late in life.’ But in is necessary to find out an authority for this.—(2).