SB 11.17.30

evaṁ-vṛtto gurukule
 vased bhoga-vivarjitaḥ
vidyā samāpyate yāvad
 bibhrad vratam akhaṇḍitam
Word for word: 
evam — thus; vṛttaḥ — engaged; gurukule — in the āśrama of the spiritual master; vaset — he should live; bhoga — sense gratification; vivarjitaḥ — freed from; vidyā — Vedic education; samāpyate — is completed; yāvat — until; bibhrat — maintaining; vratam — the vow (of brahmacarya); akhaṇḍitam — unbroken.
Translation: 
Until the student has completed his Vedic education he should remain engaged in the āśrama of the spiritual master, should remain completely free of material sense gratification and should not break his vow of celibacy [brahmacarya].
Purport: 

This verse describes the upakurvāṇa-brahmacārī, who enters gṛhastha-āśrama, or family life, after completing his Vedic education. The word evaṁ-vṛttaḥ indicates that although one may eventually marry and become prominent in society as an intellectual, politician or businessman, during student life one must remain without false prestige as a humble servant of the bona fide spiritual master. The naiṣṭhiki-brahmacārī, who never marries, is described in the following verse.