SB 10.80.33
nanv artha-kovida brahman
varnasrama-vatam iha
ye maya guruna vaca
taranty añjo bhavarnavam
Translation:
Certainly, O brahmana, of all the followers of the varnasrama system, those who take advantage of the words I speak in My form as the spiritual master and thus easily cross over the ocean of material existence best understand their own true welfare.
Purport:
One’s father is a natural object of reverence, as is a religious leader who initiates one into sacred ceremonies and instructs one in general wisdom. But ultimately the bona fide spiritual master, learned in the transcendental science and thus able to take one across the ocean of birth and death to the spiritual world — such a guru is most deserving of worship and respect, for he is the direct representative of the Supreme Personality of Godhead, as stated here.