Preachers Must Be Pure - Prabhupada 0137
721114 - Lecture NOD - Vrndavana
One who is professional, who is not Vaiṣṇava, from him, one should not hear about the holy names of God, Kṛṣṇa. That is prohibited. Because it will not be effective. Rather, it will be dangerous.
So preaching work, this Kṛṣṇa conscious preaching work, we must be very cautious that those who are preachers, they must be pure Vaiṣṇava. Anyābhilāṣitā-śūnyam (Brs. 1.1.11). Not for money's sake, not for reputation sake, lābha-pūjā-pratiṣṭhā. Only for serving Kṛṣṇa. Ānukūlyena kṛṣṇānu-śīlanam (CC Madhya 19.167). This is pure Vaiṣṇavism. One has to satisfy Kṛṣṇa. Not for any other purpose."