They call the teacher (the pupil’s) father because he gives the Veda; for nobody can perform a (sacred) rite before the investiture with the girdle of Munga grass.
नाभिव्याहारयेद् ब्रह्म स्वधानिनयनाद् ऋते । शूद्रेण हि समस्तावद् यावद् वेदे न जायते ॥ १७२ ॥
(He who has not been initiated) should not pronounce (any) Vedic text excepting (those required for) the performance of funeral rites, since he is on a level with a Sudra before his birth from the Veda.
यद्यस्य विहितं चर्म यत् सूत्रं या च मेखला । यो दण्डो यत्च वसनं तत् तदस्य व्रतेष्वपि ॥ १७४ ॥
Whatever dress of skin, sacred thread, girdle, staff, and lower garment are prescribed for a (student at the initiation), the like (must again be used) at the (performance of the) vows.
But a student who resides with his teacher must observe the following restrictive rules, duly controlling all his organs, in order to increase his spiritual merit.