Vishnupurana 3.10.14

3.10.14

brahmacaryeṇa vā kālaṃ kuryātsaṃkalpapūrvakam /
gugoḥ śuśruṣaṇaṃ kuryāttatputrāderathāpi vā //

"When he has finished his studies, and given the parting donation to his preceptor, the man who wishes to lead the life of a householder must take a wife. If he does not propose to enter into the married state, he may remain as a student with his teacher, first making a vow to that effect, and employ himself in the service of his preceptor and of that preceptor's descendants; or he may at once become a hermit, or adopt the order of the religious mendicant, according to his original determination.