“Jana sangas ca—you should not be bound by bad association. Never accept any food or water from the hands of those people who do not engage in the worship of Krishna. Don’t accept anything from them; in their association your intelligence will be destroyed. In their proximity, your bhakti should be kept confidential. Never be engaged in prolonged conversations with them, even if one of the persons happens to be your son, brother, or husband. You can meet and cheat them by speaking on worldly subject matters. But never speak on the confidential truths of bhakti. This way, you should behave accordingly.
You should always be engaged in sadhu-sanga. What is the meaning of sadhu-sanga? It means associating with a high class of a devotee who is in the line of our guru, and especially in the line of Srila Rupa Gosvami and Sri Caitanya Mahaprabhu. On finding such a sadhu, you should try to follow his association and listen to his katha.
Don’t be entangled in the association of worldly people. The association of people who have no devotion must be avoided at all costs, or else your devotion will be destroyed. This applies even to a godbrother. The godbrother may be chattering here and there, so even your godbrother’s association must be avoided. Rather, you should associate with a devotee absorbed in the devotional services of Krishna. This devotee weeps while he continuously chants the holy name, and he is much more advanced than us.” ~
Srila Gurudeva Bhaktivedanta Narayana Gosvami Maharaja (Den Haag, 14 May 1996)