SB 7.12.1
sri-narada uvaca
brahmacari gurukule
vasan danto guror hitam
acaran dasavan nico
gurau sudrdha-sauhrdah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Narada Muni said: A student should practice completely controlling his senses. He should be submissive and should have an attitude of firm friendship for the spiritual master. With a great vow, the brahmacari should live at the gurukula, only for the benefit of the guru.