Devotee: What class of men did Lord Caitanya teach about?
Prabhupāda: Those who accept Kṛṣṇa as the Supreme Personality of Godhead.
Devotee: He preached among the devotees.
Prabhupāda: His preaching begins from surrendering to Kṛṣṇa. Yāre dekha tāre kaha 'kṛṣṇa'-upadeśa (CC Madhya 7.128). Kṛṣṇa upadeśa is that Kṛṣṇa's asking everyone to surrender unto Him. So one who has surrendered unto Kṛṣṇa, he can understand Lord Caitanya's teaching. Jīvera svarūpa haya nityera kṛṣṇa-dāsa (CC Madhya 20.108). He begins His teachings from the point when one accepts that "I am eternal servant of Kṛṣṇa."
Martin: This chanting process is directed to everyone, or just those who...
Prabhupāda: No, everyone. By chanting he'll come to this point. When his heart will be cleansed, then he will come to this point to surrender to Kṛṣṇa. We initiate a person, not that he is already on that standard, but we are educating him by the process, how to come to that standard.