Manava Dharmashastra 2.243

2.243

atyantaṃ bhavamātyantikaṃ vāsaṃ guroḥ kule naiṣṭhikaṃ brahmacaryaṃ yadi rocayettadā yuktastatparaḥ paricaredenaṃ gurum—ā śarīrasya vimokṣaṇātpātād—yāvaccharīraṃ dhriyata ityarthaḥ |

Medhātithi’s commentary (manubhāṣya):
If he likes to live in absolute—i.e., life long, permanent,—residence in the Teacher’s house,—then, in that owe,—‘he should intently’—diligently—‘serve him,’—the Teacher; ‘till he becomes freed from his body,—i.e., as long as his body lasts.—(243)