Prabhupāda: He not only worships the Deity wholeheartedly . . . That is prema. Īśvare prema. But beyond that, tad adhīneṣu—he knows how to respect the devotees, tad adhīneṣu. Īśvara adhīneṣu, that means other devotees. Then he becomes madhyama-adhikārī. If he simply takes care of the Deity worship and if he does not offer respectful behavior to another devotee, he is kaniṣṭha-adhikārī. He is in the lower stage. So īśvare tad adhīneṣu. He must see that "Here is a devotee." He must have power to see that "Here is a devotee."
So how to deal with devotee? Maitrī: to make friendship with him. Īśvare prema. And to the devotees, friendship; not with others, friendship. Caitanya Mahāprabhu advised. When He was asked by a gṛhastha devotee how to behave like a Vaiṣṇava, what is the behavior of a Vaiṣṇava, He immediately answered that the standard Vaiṣṇavism is asat-saṅga-tyāga,—ei vaiṣṇava-ācāra (CC Madhya 22.87): "He must give up the company of asat, nondevotees." Asato mā sad gamaḥ: don't associate with nondevotee. If you want to make progress, don't associate. Associate does not mean to talk with a nondevotee is association. No. That we have to do. As gentlemen, as devotee, we can. But not intimately. Associate means dadāti pratigṛhṇāti bhuṅkte bhojayate caiva, guhyam ākhyāti pṛcchati ca (Upadeśāmṛta 4). These are intimate relationship, dealing: giving something to your friend, accepting something from your friend, feeding your friend, accept food from him, and disclose your mind to your friend and understand his mind. Ṣaḍ-vidhaṁ prīti-lakṣaṇam (Upadeśāmṛta 4).