Manava Dharmashastra 4.93

4.93

anantaraṃ prabhātāyāṃ rātrau śayanaṃ jahyāt | āvaśyakaṃ mūtraviṭtyāgaḥ | prāyeṇa tasyāṃ velāyāṃ puruṣāstaṃ kurvanti | tatra āvaśyakastyāga ucyate-mukhadantadhāvanādiśca taṃ kṛtvā kṛtaśaucaḥ | ‘ekā liṅge’tyādividhinā''cāntaḥ | samāhito vikalpāntaratiraskāreṇa sandhyāṃ tiṣṭhet | japansāvitrīṃ bhagavati savitari mano dadhyāt ‘ciram’ | arkadarśanāvadhiḥ kāla uktaḥ ‘sandhyāsamayaḥ’ | tato'pyadhikaṃ kālaṃ japedāyuḥkāma ityevamarthamayaṃ prāguktaḥ sāndhyo vidhirantarhitaḥ | aparāṃ ca sandhyāṃ sve kāle astamayasamayādārabhya tārakodayādūrdhvamapi |

Having risen, and saving accomplished the necessities of nature, he shall perform the purifications, and, with collected mind, he shall stand, repeating for a long time (the Sāvitrī), during the morning-twilight, as also during the evening-twilight, at its proper time.’—(93).

Medhātithi’s commentary (manubhāṣya):
When the night has passed and the dawn appeared, he should leave his bed.

‘Necessities of nature.’— Evacuating of the bladder and of the bowels. As a rule, people do this act at that time; hence the evacuating has been called a ‘necessity.’

‘Purifications;’—i.e., brushing of the teeth, &c.; having done all this; this is what is meant by ‘performing the purifications;’—i.e., having washed and cleansed himself, according to the rules laid down in 5.136.

‘With a collected mind;’—i.e., withdrawing his mind from all other thoughts.

‘He shall stand during the morning twilight,—repeating—the Sāvitrī;—he shall fix his mind upon the god Sun—‘for a long time.’

The time of ‘twilight’ has been described as extending up to the appearance of the Sun; and even longer than this, one shall go on repeating the Sāvitrī, if he desire longevity. It is for the adding of this prolongation that the afore mentioned Injunction regarding the Twilight Prayers (See 2.101) has been reiterated. ‘Also during the evening twilight,—at its proper time;’—i.e., beginning from sunset and prolonging it till after the appearance of the stars—(93)

This verse is quoted in Vīramitrodaya (Āhnika, p. 13).

Comparative notes by various authors
Mahābhārata (Anuśāsana, 104.16).—‘Rising from the bed, with joined hands he shall offer the morning Twilight Prayer.’

Viṣṇu (71.77).—‘For a long time he shall continue the Twilight Prayer.’

Aṅgiras (Vīramitrodaya-Āhnika, p. 19).—‘Rising during the last quarter of the night, one should give up the cloth worn during the night, and having washed his hands, feet and face, think of Hari.’

Kātyāyana (Do., p. 20).—‘Rising, washing his eyes and becoming clean, etc.’