This cultivation of Kṛṣṇa consciousness is not material. The Lord has generally three energies—namely, the external energy, the internal energy, and the marginal energy. The living entities are called marginal energy, and the material cosmic manifestation is the action of the external or material energy. Then there is the spiritual world, which is a manifestation of the internal energy. The living entities, who are called marginal energy, perform material activities when acting under the inferior external energy. And when they engage in activities under the internal spiritual energy, their activities are called Kṛṣṇa conscious. This means that those who are great souls or great devotees do not act under the spell of material energy, but act instead under the protection of the spiritual energy. Any activities done in devotional service or in Kṛṣṇa consciousness are directly under the control of spiritual energy. In other words, energy is a sort of strength, and this strength can be spiritualized by the mercy of both the bona fide spiritual master and Kṛṣṇa.
In the Caitanya-caritāmṛta by Kṛṣṇadāsa Kavirāja Gosvāmī, Lord Caitanya states that it is a fortunate person who comes in contact with a bona fide spiritual master by the grace of Kṛṣṇa. One who is serious about spiritual life is given by Kṛṣṇa the intelligence to come in contact with a bona fide spiritual master, and then by the grace of the spiritual master one becomes advanced in Kṛṣṇa consciousness. In this way the whole jurisdiction of Kṛṣṇa consciousness is directly under the spiritual energy—Kṛṣṇa and the spiritual master. This has nothing to do with the material world. When we speak of Kṛṣṇa we refer to the Supreme Personality of Godhead, along with His many expansions. He is expanded by His plenary parts and parcels, His differentiated parts and parcels and His different energies. Kṛṣṇa, in other words, means everything and includes everything. Generally, however, we should understand Kṛṣṇa to mean Kṛṣṇa and His personal expansions. Kṛṣṇa expands Himself as Baladeva, Saṅkarṣaṇa, Vāsudeva, Aniruddha, Pradyumna, Rāma, Nṛsiṁha and Varāha, as well as many other incarnations and innumerable Viṣṇu expansions. These are described in the Śrīmad-Bhāgavatam to be as numerous as the uncountable waves. So Kṛṣṇa includes all such expansions, as well as His pure devotees. In the Brahma-saṁhitā it is stated that Kṛṣṇa's expansions are all complete in eternity, blissfulness and cognizance.
Devotional service means to prosecute Kṛṣṇa conscious activities which are favorable to the transcendental pleasure of the Supreme Lord Kṛṣṇa, and any activities which are not favorable to the transcendental favor of the Lord cannot be accepted as devotional service. For example, great demons like Rāvaṇa, Kaṁsa and Hiraṇyakaśipu were always thinking of Kṛṣṇa, but they were thinking of Him as their enemy. This sort of thinking cannot be accepted as bhakti or Kṛṣṇa consciousness.
The impersonalists sometimes misunderstand devotional service in such a way that they divide Kṛṣṇa from His paraphernalia and pastimes. For example, the Bhagavad-gītā is spoken on the battlefield of Kurukṣetra, and the impersonalists say that although Kṛṣṇa is of interest, the battlefield of Kurukṣetra isn't. The devotees, however, also know that the battlefield of Kurukṣetra by itself has nothing to do with their business, but in addition they know that "Kṛṣṇa" does not mean just Kṛṣṇa alone. He is always with His associates and paraphernalia. For instance, if someone says, "Give something to eat to the man with the weapons," the eating process is done by the man and not by the weapons. Similarly, in Kṛṣṇa consciousness, a devotee may be interested in the paraphernalia and locations—such as the battlefield of Kurukṣetra—which are associated with Kṛṣṇa, but he is not concerned with simply any battlefield. He is concerned with Kṛṣṇa—His speech, His instructions, etc. It is because Kṛṣṇa is there that the battlefield is so important.