Śrī Nārada Muni is a naiṣṭhika-brahmacārī. There are four types of brahmacārīs. The first is called sāvitra, which refers to a brahmacārī who, after initiation and the sacred thread ceremony, must observe at least three days of celibacy. The next is called prājāpatya, which refers to a brahmacārī who strictly observes celibacy for at least one year after initiation. The next is called brāhma-brahmacārī, which refers to a brahmacārī who observes celibacy from the time of initiation up to the time of the completion of his study of the Vedic literature. The next stage is called naiṣṭhika, which refers to a brahmacārī who is celibate throughout his whole life. Out of these, the first three are upakurvāṇa, which means that the brahmacārī can marry later, after the brahmacārī period is over. The naiṣṭhika-brahmacārī, however, is completely reluctant to have any sex life; therefore the Kumāras and Nārada are known as naiṣṭhika-brahmacārīs. Such brahmacārīs are called vīra-vrata because their vow of celibacy is as heroic as the vows of the kṣatriyas. The brahmacārī system of life is especially advantageous in that it increases the power of memory and determination. It is specifically mentioned in this connection that because Nārada was a naiṣṭhika-brahmacārī he could remember whatever he heard from his spiritual master and would never forget it. One who can remember everything perpetually is called a śruti-dhara. A śruti-dhara brahmacārī can repeat verbatim all that he has heard, without notes and without reference to books. The great sage Nārada has this qualification, and therefore, having taken instructions from Nārāyaṇa Ṛṣi, he is engaged in propagating the philosophy of devotional service all over the world. Because such great sages can remember everything, they are thoughtful, self-realized and completely fixed in the service of the Lord.
Thus the great sage Nārada, after hearing from his spiritual master Nārāyaṇa Ṛṣi, became completely realized. He became established in the truth, and he became so happy that he offered prayers to Nārāyaṇa Ṛṣi. Nārada Muni addressed Nārāyaṇa Ṛṣi as an incarnation of Kṛṣṇa and specifically addressed Him as the supreme well-wisher of the conditioned souls. It is stated in the Bhagavad-gītā that Lord Kṛṣṇa descends in every millennium just to give protection to His devotees and to annihilate the nondevotees. Nārāyaṇa Ṛṣi, being an incarnation of Kṛṣṇa, is also addressed as the well-wisher of the conditioned souls. As stated in the Bhagavad-gītā, everyone should know that there is no well-wisher like Kṛṣṇa. Everyone should understand that Lord Kṛṣṇa is the supreme well-wisher of everyone and should take shelter of Him. In this way one can become completely confident and satisfied, knowing that he has someone who is able to give him all protection. Kṛṣṇa Himself, His incarnations and His plenary expansions are all supreme well-wishers of the conditioned souls, but Kṛṣṇa is the well-wisher even of the demons, for He gave salvation to all the demons who came to kill Him in Vṛndāvana; therefore Kṛṣṇa's welfare activities are absolute, for whether He annihilates a demon or gives protection to a devotee, the result of His activities is one and the same. It is said that the demon Pūtanā was elevated to the same position as that of Kṛṣṇa's mother. When Kṛṣṇa kills a demon, the demon is supremely benefited, as much as a pure devotee is benefited by always being protected by the Lord.
Nārada Muni, after offering respects to Nārāyaṇa Ṛṣi, went to the āśrama of Vyāsadeva, his disciple. Being properly received by Vyāsadeva in his āśrama and seated very comfortably, Nārada Muni narrated the entire story of what he had heard from Nārāyaṇa Ṛṣi. In this way Śukadeva Gosvāmī informed Mahārāja Parīkṣit of the answers to his questions regarding the essence of Vedic knowledge and what is considered to be the ultimate goal in the Vedas. The supreme goal of life is to achieve the transcendental blessings of the Supreme Personality of Godhead and thus become engaged in the loving service of the Lord. One should follow in the footsteps of Śukadeva Gosvāmī and all the other Vaiṣṇavas in the disciplic succession and should pay respectful obeisances unto Lord Kṛṣṇa, the Supreme Personality of Godhead, Hari. The four sects of Vaiṣṇava disciplic succession, namely the Madhva-sampradāya, the Rāmānuja-sampradāya, the Viṣṇu-svāmi-sampradāya and the Nimbārka-sampradāya, in pursuance of all Vedic conclusions, agree that one should surrender unto the Supreme Personality of Godhead.
The Vedic literature is divided into two parts: the śrutis and the smṛtis. The śrutis are the four Vedas—Ṛg, Sāma, Atharva and Yajur—and the Upaniṣads, and the smṛtis are the Purāṇas and the Itihāsas like the Mahābhārata, which includes the Bhagavad-gītā. The conclusion of all these is that one should know Śrī Kṛṣṇa as the Supreme Personality of Godhead. He is the Parama-puruṣa, or the Supreme Personality of Godhead, under whose superintendence material nature works. For creation, maintenance and annihilation, the Supreme Lord incarnates into three—Lord Brahmā, Lord Viṣṇu and Lord Śiva—after manifesting the material cosmos. All of these take charge of the three modes of material nature, but the ultimate direction is in the hand of Lord Viṣṇu. The complete activities of material nature under the three modes are conducted under the direction of the Supreme Personality of Godhead, Kṛṣṇa. This is confirmed in the Bhagavad-gītā (mayādhyakṣeṇa (BG 9.10)) and in the Vedas (sa aikṣata).
The atheistic Sāṅkhyaite philosophers will of course offer their arguments that the material cosmic manifestation is due to prakṛti and puruṣa—material nature and the living entity, or the material cause and the effective cause. But Kṛṣṇa is the cause of all causes. He is the cause of both the material and the effective causes. Prakṛti and puruṣa are not the ultimate cause. Superficially it appears that a child is born due to the combination of the father and mother, but the ultimate cause of both the father and the mother is Kṛṣṇa. He is therefore the original cause, or the cause of all causes, as confirmed in the Brahma-saṁhitā.
Both the Supreme Lord and the living entities enter into the material nature. The Supreme Lord, Kṛṣṇa, by one of His plenary expansions, manifests as Kāraṇodakaśāyī, Mahā-Viṣṇu, the gigantic Viṣṇu form lying in the Causal Ocean. Then from that gigantic form of Mahā-Viṣṇu, Garbhodakaśāyī Viṣṇu expands and enters into every universe. From Him, Brahmā, Viṣṇu and Śiva expand. Viṣṇu as Kṣīrodakaśāyī enters into the hearts of all living entities, as well as into all material elements, including the atom. The Brahma-saṁhitā says, aṇḍāntara-stha-paramāṇu-cayāntara-stham: (Bs. 5.35) "The Lord is within this universe and also within every atom."