Manava Dharmashastra 2.193

2.193

na kevalaṃ sūtrakātpāṇiruddharttavyo'pitu vāsaso'pi | nityagrahaṇaṃ—na tiṣṭhata evāyaṃ pāṇyuddhāraḥ, nāpyadhyayanavelāyām, kiṃ tarhi tato'nyatrāpi | sādhvācāraḥ sādhuḥ anindyaḥ ācāro vāgvyavahārādiḥ kāryaḥ | aślīlādibhāṣāmasannidhāne'pi gurornityagrahṇānna karttavyam | susaṃvṛtaḥ vāṅmanaścakṣubhiḥ niyatātmā | svalpo'pi yo doṣastaṃ pariharet | anāvṛto loka ucyate yo yathākāmī; tadviparītaḥ susaṃvṛtaḥ | anye tu manyante—vastreṇācchāditaśarīro gurusannidhau bhavennottarīyamavatārayet | evaṃ tiṣṭhet | yadā tu guruṇā āsyatāmityuktaḥ—etena śabdena bhrū vikṣepādināṃ vā--vidheḥ pratipādanārthatvāt, pratipādanaṃ ca na śabdavyāpāra eva | tadā āsīta upaviśet | abhimukhaṃ sammukham |

He should always have his arm raised, remain well behaved, and well-guarded; when addressed with the words “be seated,” he should sit facing his teacher.—(193)

Medhātithi’s commentary (manubhāṣya):
The arm should be raised, not only above the saered thread, but also out of the upper garment.

The adverb ‘always’ is meant to imply that the arm is to be raised not only while he is standing, nor only while he is reading, but on other occasions also.

‘Well-behaved’;—he should have his behaviour—speech and other acts—good, above reproach. The word ‘implies that even when not near the Teacher, he should not utter indecorous words, or do any such wrongful act.

‘Well-guarded’;—i.e., fully self-controlled, regarding speech, mind and eyes,—he should avoid even the slightest defects. The man who follows the bent of his desires (and does not restrain them) is called among people ‘unguarded’; and the opposite of this is ‘well-guarded.’

Others explain this to mean that ‘near his Teacher one should keep his body covered, and he should not take off his upper garment.’

In the manner thus described, ‘he should stand’ (as laid down in the preceding verse); but when the Teacher says to him ‘be seated’—either in so many words, or by the gesture of his brows, etc.; the function of the injunction being to convey the direction, and this conveying need not be done only by means of words,—‘he should sit.’

‘Facing his Teacher’—with his face towards the Teacher.—(198)