Srila Bhaktivinoda Thakura
Sanga-tyaga
Everyone in the world is under the control of these two kinds of prejudices. When a living entity is not bound by maya, then by nature he is a servant of Krsna. Being bound by maya, a living entity cannot give up ancient and modern wicked prejudices. At that time ancient wicked prejudices become his second nature. Only sadhu-sanga can reform the attachment to prejudices. Sadhu-sanga is the only remedy for this disease. Unless one reforms his attachment to prejudices, one cannot attain perfection in devotional service by any means. As stated in the Srimad Bhagavatam (3.23.55):
sango yah samsrter hetur asatsu vihito 'dhiya
sa eva sadhusu krto nihsangatvaya kalpate
Due to association with materialistic people, the living entity is bound in the cycle of birth and death. Even if one unknowingly associates with a materialist, the result must come. And if one unknowingly associates with a real sadhu, he attains freedom from material association. Again in Srimad Bhagavatam (11.12.1-2) it says:
no rodhayati mam yogo na sankhyam dharma eva ca
na svadhyayas tapas tyago nesta-purtam na daksina
vratani yajnas chandamsi tirthani niyama yamah
yathavarundhe sat-sangah sarva-sangapaho hi mam