This is called kīrtana. And by his mind a Kṛṣṇa conscious person always thinks of the activities of the Lord—as He is speaking on the Battlefield of Kurukṣetra or engaging in His various pastimes in Vṛndāvana with His devotees. In this way one can always think of the activities and pastimes of the Lord. This is the mental culture of Kṛṣṇa consciousness.
Similarly, we can offer many services with our bodily activities. But all such activities must be in relationship with Kṛṣṇa. This relationship is established by connecting oneself with the bona fide spiritual master, who is the direct representative of Kṛṣṇa in disciplic succession. Therefore, the execution of Kṛṣṇa conscious activities with the body should be directed by the spiritual master and then performed with faith. The connection with the spiritual master is called initiation. From the date of initiation by the spiritual master, the connection between Kṛṣṇa and a person cultivating Kṛṣṇa consciousness is established. Without initiation by a bona fide spiritual master, the actual connection with Kṛṣṇa consciousness is never performed.