Skandapurana 2.9.21

Glorious Nārāyaṇa said:

The student, the householder, the forest-dweller, and the renunciant—

these four are declared to be the persons of the life-stages, O best of sages. (1)

He who is purified by the life-cycle rites, of pure womb, and has attained twice-born status,

he indeed is a student; I will explain his duties from the beginning. (2)

Living pure in the teacher's house, the student should study the Veda,

with senses subdued, anger conquered, humble, and speaking the truth. (3)

Evening and morning, self-restrained, he should perform the fire oblation and go begging for alms;

he should perform the twilight devotion at the three junctures of the day, and likewise worship of Viṣṇu every day. (4)

Only by the teacher's command should he eat a measured amount of food, undisturbed;

he should be constantly devoted to the service of the teacher and free from vices. (5)

During bathing, eating, fire oblation, and silent recitation, he should maintain silence;

he should not cut his nails or hair, nor scrub his teeth excessively. (6)

He should not excessively wash his clothes, and he should be guileless toward the teacher;

summoned, he should study, and at the beginning and the end he should bow to him. (7)

He should not touch untouchables, nor speak to those with whom conversation is forbidden;

he should never eat uneatable food, nor drink undrinkable liquid. (8)

He should wear a girdle, a hide, a staff, and carry a water-pot,

two white garments, a sacred thread, and a rosary. (9)

With kuśa grass in hand, having matted locks, free of hair ornamentation,

he should avoid body-ointments, flower garlands, and ornaments. (10)

He should not rub himself with oil, nor apply collyrium with lamp-black;

and with effort he should avoid contact with intoxicating liquor and meat. (11)

Gazing at, touching, speaking with, or playing with women,

and even a drawing of a woman, the student must avoid in every way. (12)

Except for an image of a deity, a woman made of wood, painted, and the like,

the wise [student] should not touch at all, nor deliberately look upon. (13)

And he should never gaze upon any living creature in copulation;

he should not listen to the virtues or defects of women, nor speak of them. (14)

Without touching, he should salute even his own teacher's wife;

and he should never stay in a secluded place even with his mother. (15)

Behaving in this manner, he should dwell there until the completion of his studies.

Then, detached, he may become a renunciant, or he may become a lifelong student. (16)

In the Kali [age], ineligibility is stated for those observing lifelong celibacy (naiṣṭhika).

It should be understood that this does not apply to the twilight [of the yuga], from the concise usage of the word 'Kali'.

O brahmin, he may become a forest dweller, or if not dispassionate, he should become a householder.

Prājāpatya, Sāvitra, Brāhma, and Naiṣṭhika—

such is the fourfold brahmacarya; of these, one should adhere to one according to one's capacity.

Thus ends the twenty-first chapter, entitled 'Determination of the Duties of a Brahmacārin', in the Vāsudeva-māhātmya of the second [section], the Vaiṣṇavakhaṇḍa, in the Skanda Mahāpurāṇa of eighty-one thousand verses. // 21