SB 7.12.3
chandamsy adhiyita guror
ahutas cet suyantritah
upakrame ’vasane ca
caranau sirasa namet
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Being called by the spiritual master, the student should study the Vedic mantras regularly. Every day, before beginning his studies and at the end of his studies, the disciple should respectfully offer obeisances unto the spiritual master.