Bhajana Rahasya: Dealing with Vaishnavas
kṛṣṇeti yasya giri taṁ manasādriyeta
dīkṣāsti cet praṇatibhiś ca bhajantam īśam
śuśrūṣayā bhajana-vijñam ananyam anya-
One should mentally honor the devotee who chants the holy name of Lord Krishna. One should offer his humble obeisances to the one who has undergone spiritual initiation [dīkṣā] and is engaged in worshiping the Deity. And if one encounters a pure devotee who is advanced in undeviating devotional service and whose heart is completely devoid of the propensity to criticize others, one should associate with and faithfully serve him, recognizing him to be the ideal spiritual companion.
Bhaktivinode Thakur's translation in Bhajana-rahasya:
If you hear someone sincerely chanting the Holy Name, then you should offer him respects in your mind, again and again.
If he has joined a devotional disciplic line (sampradaya) through initiation and is engaged in worshiping Krishna, then you should respectfully fall down and take the dust of his feet.
And if you meet a devotee who has no concept of anyone belonging to his or to an opposing group, and is simply engaged in undeviating devotion to Krishna, then serve him constantly.
There is a clear relationship of this verse with the divisions of kaniṣṭha, madhyama and uttama. But the correspondence is not exact in all cases. You have to adjust the qualities. This is why we sometimes go into kanishtha-kanishtha, madhyama-kanishtha and so on.
This article was a stub that I hadn't finished.