The body is the field of activity; the soul is its knower—spiritual realization is life's true perfection.Listen — Srila Prabhupada Uvaca
Bhagavad-gītā 13.1–2 — September 24, 1973, Bombay 730924BG-BOMBAY [21:04 Minutes] Bg-13.01–02_730924BG-BOMBAY Prabhupāda: "Nature, the Enjoyer and Consciousness." This is the Thirteenth Chapter of Bhagavad-gītā. The Lord is describing what is this material nature, who is the enjoyer of this material nature and what is the consciousness. We are preaching about Kṛṣṇa consciousness. Now, in this chapter Kṛṣṇa Himself is describing what is Kṛṣṇa consciousness.
Arjuna uvāca, Arjuna inquired: prakṛtiṁ puruṣaṁ caiva kṣetraṁ kṣetrajñam eva ca etad veditum icchāmi jñānaṁ jñeyaṁ ca keśava [Bg. 13.1] Kṛṣṇa is addressed here as Keśava, "the killer of the Keśi asura." You know, in Vṛndāvana, there is Keśi-ghāṭa. That Keśi-ghāṭa is famous because Kṛṣṇa killed one asura of the name Keśi. He appeared in Vṛndāvana as a ferocious horse, and Kṛṣṇa killed him. Since then, His name is Keśava.
Kṛṣṇa has got many names according to His activities. He killed the demon Madhu, therefore His name is Madhusūdana. He killed the demon Kaṁsa, therefore His name is Kaṁsāri[?]. There are many names.
Some of the names are in relationship with His devotees, and some of the names are there in relationship with the demons. There are two kinds of men: the devotees and the demons. Daiva āsura eva ca. dvau bhūta-sargau loke daiva āsura eva ca viṣṇu-bhakto bhaved daiva āsuras tad viparyayaḥ [Bg. 16.6] Throughout the universe there are two classes of men. One is called devatā and the other is called asura.
Devata means visnu-bhakto bhaved daivaḥ. Those who are devotees of the Supreme Personality of Godhead, who is known as Viṣṇu... Viṣṇu has got... Sahasra viṣṇu names there are.
Original is Viṣṇu. So those who are devotees of the Lord, they are called Vaiṣṇava or devatā, and those who are not devotees of Viṣṇu may be devotees of other demigods, but they are called the demons, or the asuras. There are many instances in the śāstra. There were Hiraṇyakaśipu, who was a devotee of Lord Brahmā.
Of course, the asuras are never devotees. Sometimes they worship the demigods for getting some material profit. Kāṅkṣantaḥ karmaṇāṁ siddhiṁ yajanta iha devatāḥ [Bg. 4.12]. That is said in the Bhagavad-gītā.