One who eradicates the ajñāna, andhakāra, darkness. In the darkness, if somebody brings lamp, ajñāna-timirāndhasya jñānāñjana-śalākayā . . . the jñāna-rūpa, torchlight, he's guru. So maybe different degrees, but anyone who opens the spiritual eyes, he's guru. So . . .
But in the śāstra it is said, gurur api kāryākāryakam ajānataḥ. If I accept some guru, but if later on it appears that he did not know what is to be done, what is to be not to be done, then Śrīla Jīva Gosvāmī says that such guru: parityāgo vidhīyate. Such guru should be rejected. But it doesn't matter that degree. Actually, if the guru teaches Kṛṣṇa consciousness, then he may be in lesser degree, but he's accepted as guru. There is no question of rejection.
Because Kṛṣṇa is actually jñāna. One who teaches Kṛṣṇa as the Supreme Personality of Godhead, "One has to know Kṛṣṇa, one has to surrender to Kṛṣṇa," this kind of teaching is required. And if the guru says that, "I am Kṛṣṇa. Everyone is Kṛṣṇa," then, "daridra-kṛṣṇa, daridra-nārāyaṇa," he is not a guru. He's not a guru. He's misguiding. Misguiding. Avaiṣṇavo gurur na syāt. This is the śāstric injunction.
Ṣaṭ-karma-nipuṇo vipro mantra-tantra-viśāradaḥ. A . . . generally, a qualified brāhmin becomes guru. That is natural. brāhmin is the head of the society. So he is . . . and without becoming brāhmin, nobody can become guru. That is also fact. Because brāhmin means brahma jānātīti brāhmanaḥ, one who knows Brahman, Brahman. So guru must be a brāhmin, mean a qualified brāhmin, not born-brāhmin, so-called brāhmin. Qualified brāhmin.
So still, brāhmin's qualification, ṣaṭ-karma: paṭhana pāṭhana yajana yājana dāna pratigraha. So śāstra says that ṣaṭ-karma-nipuṇo vipraḥ. If one vipra is quite expert in executing the six kinds of business, and mantra-tantra-viśāradaḥ, and very well known in the Vedic mantras and hymns and everything complete, but if he is avaiṣṇava, if he is not Vaiṣṇava, he does not know viṣṇu-tattva, or kṛṣṇa-tattva, then he cannot become spiritual master.
Avaiṣṇavo gurur na syād vaiṣṇavaḥ śva-paco guruḥ. But if a Vaiṣṇava, one who knows viṣṇu-tattva, kṛṣṇa-tattva, even if he's born in the family of śva-paca, the dog-eaters, caṇḍāla, he can be accepted as guru.