Ṣaṭ-karma-nipuṇaḥ. Brāhmin have got six kinds of occupation: paṭhana-pāṭhana yajana-yājana dāna-pratigraha. Brāhmin should be very learned, he should teach others also Vedic knowledge, paṭhana-pāṭhana. Yajana-yājana. He must be a devotee or great worshiper, and he should teach others also how to worship. Yajana-yājana. Dāna-pratigraha. He will accept charity from others, and he will give in charity again to others. These are the six occupation of a brāhmin.
So śāstra says, ṣaṭ-karma-nipuṇo vipraḥ: "A brāhmin, well conversed with these duties of brahminical duties," and mantra-tantra-viśāradaḥ, "And expert in studying the mantras, Vedic mantras, and tantra, other Vedic literature," avaiṣṇavo gurur na sa syāt, "But if he is avaiṣṇava," means he does not worship Lord Viṣṇu but other demigods, "Then he cannot become guru." That is not allowed. You cannot become guru. Ṣaṭ-karma-nipuṇo vipro mantra . . .
So this Śukrācārya, he was against Viṣṇu. So Bali Mahārāja immediately rejected him. Therefore he became a mahājana, exemplary. Because you cannot give up your spiritual master. That is a great sin. Once accepted, the spiritual master takes responsibility for the disciple. And disciple also must be obedient to the spiritual master for life, for good. That is the relationship.
So if one rejects spiritual master, he becomes a great sinner, most sinful. So Bali Mahārāja rejected his spiritual master. That's a great sin. But he rejected on śāstric ground, because he objected for Viṣṇu worship. Therefore such spiritual master should be rejected. Should be rejected. Therefore he became mahājana, authority.
Anyone who is obstruction to worship the Supreme Lord, he should be rejected immediately. That is bhakti. Ānukūlyasya saṅkalpa prātikūlyam varjanam. Anything favorable for advancement of Kṛṣṇa consciousness should be accepted; anything unfavorable, that should be rejected. This is śaraṇāgati. Ānukūlyena kṛṣṇānuśīlanam (CC Madhya 19.167).
We have to worship Kṛṣṇa, whatever is favorable. It is not that because the microphone is material, therefore I cannot use it. There are some so-called transcendentalists . . . why not? If I speak through the microphone, I can serve better Kṛṣṇa. Why shall I not accept it? So ānukūlyena kṛṣṇānuśīlanam: anything which is favorable for serving Kṛṣṇa, we shall accept. After all, everything belongs to Kṛṣṇa. Īśāvāsyam idaṁ sarvam (ISO 1). Nothing belongs to you. Simply we are thieves. We are using Kṛṣṇa's property for our own sense gratification. Stena eva sa ucyate (BG 3.12). All thieves.