Prabhupada's lecture - Śrīmad-Bhāgavatam 1.15.34 - Los-Angeles, December 12, 1973
So therefore association is so important. Saṅgāt sañjāyate kāmaḥ. According to association we infect different qualities. That they do not know. But nature's law is so particular, as soon as you infect by association a particular type of quality, you have to suffer for that. Therefore Caitanya Mahāprabhu, He was asked by one devotee, gṛhastha devotee, householder, "Sir, what is the duty of a gṛhastha devotee, Vaiṣṇava?" Devotee means Vaiṣṇava. So He immediately informed him, asat-saṅga-tyāga ei vaiṣṇava-ācāra: [Cc. Madhya 22.87] "A Vaiṣṇava's behavior should be that he should give up the company of asat, nondevotee." That is his first business. He should give up the company of nondevotee. This is first business. Because he will be infected.
Therefore we insist our students that "Don't go out." Even you are discomfortable, you should tolerate, but you should not go out of the society. Then you will surely fall down, surely fall down. So if there is inconvenience, little... That is advised in Bhagavad-gītā, mātrā-sparśās tu kaunteya śītoṣṇa-sukha-duḥkha-dāḥ [Bg. 2.14]. These, just like extreme cold or extreme heat, they are troublesome to the body, mātrā-sparśāḥ. On account of this material body, we feel extreme cold, extreme heat. But Kṛṣṇa says, "They come and go." It is not that winter season will remain forever or the summer season also remain. They will come and go. If it is intolerable, please tolerate, please tolerate. Then it will be all right. I have repeatedly said... Narottama dāsa Ṭhākura, tāṅdera caraṇa-sevi-bhakta-sane vāsa. Why we have opened this society? I could have initiated, and let him remain at his home. No. The society required. So by association we become good or bad. If you associate with goodness, then you acquire goodness quality, and if you associate with bad, passionate, ignorant, then you get that quality. So according to that quality...