CC Ādi 7.67
ki kāraṇe āmā-sabāra nā kara darśane
A Vaiṣṇava sannyāsī or a Vaiṣṇava in the second stage of advancement in spiritual knowledge can understand four principles — namely, the Supreme Personality of Godhead, the devotees, the innocent and the jealous — and he behaves differently with each. He tries to increase his love for Godhead, make friendship with devotees and preach Kṛṣṇa consciousness among the innocent, but he avoids the jealous who are envious of the Kṛṣṇa consciousness movement. Lord Caitanya Mahāprabhu Himself exemplified such behavior, and this is why Prakāśānanda Sarasvatī inquired why He did not associate or even talk with them. Caitanya Mahāprabhu confirmed by example that a preacher of the Kṛṣṇa consciousness movement generally should not waste his time talking with Māyāvādī sannyāsīs, but when there are arguments on the basis of śāstra, a Vaiṣṇava must come forward to talk and defeat them in philosophy.
According to Māyāvādī sannyāsīs, only one who takes sannyāsa in the disciplic succession from Śaṅkarācārya is a Vedic sannyāsī. Sometimes it is challenged that the sannyāsīs who are preaching in the Kṛṣṇa consciousness movement are not genuine because they do not belong to brāhmaṇa families, for Māyāvādīs do not offer sannyāsa to one who does not belong to a brāhmaṇa family by birth. Unfortunately, however, they do not know that at present everyone is born a śūdra (kalau śūdra-sambhavaḥ). It is to be understood that there are no brāhmaṇas in this age because those who claim to be brāhmaṇas simply on the basis of birthright do not have the brahminical qualifications. However, even if one is born in a non-brāhmaṇa family, if he has the brahminical qualifications he should be accepted as a brāhmaṇa, as confirmed by Śrīla Nārada Muni and the great saint Śrīdhara Svāmī. This is also stated in Śrīmad-Bhāgavatam. Both Nārada and Śrīdhara Svāmī completely agree that one cannot be a brāhmaṇa by birthright but must possess the qualities of a brāhmaṇa. Thus in our Kṛṣṇa consciousness movement we never offer the sannyāsa order to a person whom we do not find to be qualified in terms of the prescribed brahminical principles. Although it is a fact that unless one is a brāhmaṇa he cannot become a sannyāsī, it is not a valid principle that an unqualified man who is born in a brāhmaṇa family is a brāhmaṇa whereas a brahminically qualified person born in a non-brāhmaṇa family cannot be accepted. The Kṛṣṇa consciousness movement strictly follows the injunctions of Śrīmad-Bhāgavatam, avoiding misleading heresy and manufactured conclusions.