How a Vaiṣṇava should behave, how he should maintain his standard, Caitanya Mahāprabhu says in one word: asat-saṅga-tyāgī vaiṣṇava-ācāra. Just like Kṛṣṇa says, satāṁ prasaṅga mama vīrya-saṁvido. One can develop Kṛṣṇa consciousness in association with devotee. The same thing Caitanya Mahāprabhu said in a different way: asat-saṅga-tyāgī, not to associate with non-devotees. That is vaiṣṇava-ācāra.
So in future we shall be very careful, all the devotees, not to talk with rascals, non-devotees. It will impure, it will have poisonous effect; and that will kill Kṛṣṇa consciousness. I do not know how this man was allowed to stay here for so many months. Nobody could detect that, "Here is a serpent"? So you should be very careful in future.
That is very easy to understand, who is a serpent. So Caitanya Mahāprabhu has said. Because one may inquire, "Who is asat? How can I understand?" Asat eka strī-saṅgī kṛṣṇābhakta. Asat means who is attached to . . . very much attached to woman. You see that man, he was posing himself as yogī, and he is living with one woman. He, it was God's grace that he came with that woman so that he disclosed himself. By Kṛṣṇa's grace. Asat eka strī-saṅgī kṛṣṇābhakta. Strī-saṅgī. One should not be attached to any woman except his wife. Then he becomes asat.