SB 11.17.29
susrusamana acaryam
sadopasita nica-vat
yana-sayyasana-sthanair
nati-dure krtañjalih
Translation:
While engaged in serving the spiritual master one should remain as a humble servant, and thus when the guru is walking the servant should humbly walk behind. When the guru lies down to sleep, the servant should also lie down nearby, and when the guru has awakened, the servant should sit near him, massaging his lotus feet and rendering other, similar services. When the guru is sitting down on his asana, the servant should stand nearby with folded hands, awaiting the guru’s order. In this way one should always worship the spiritual master.