The third-class devotee engages in devotional service according to the directions of the spiritual master, or engages out of family tradition, and worships the Deity of the Lord, but he has not cultivated knowledge of devotional service, and he does not know a devotee from a nondevotee. Such a third-class devotee cannot actually be considered a pure devotee; he is almost in the devotional line, but his position is not very secure.
One can thus conclude that when a person shows love for God and friendship for devotees, displays mercy toward the innocent and is reluctant to associate with nondevotees, he may be considered a pure devotee. By developing devotional service, such a person can perceive that every living entity is part and parcel of the Supreme. In each and every living entity he can see the Supreme Person, and therefore he becomes highly developed in Kṛṣṇa consciousness.