We understand that with the breathing of the Supreme Personality of Godhead there issued forth the four Vedas, namely the Ṛg Veda, the Yajur Veda, the Sāma Veda and the Atharva Veda, and also the histories like the Mahābhārata and all the Purāṇas, which are considered to be the history of the world. The Vedic histories like the Purāṇas and Mahābhārata are called the fifth Veda.
The twenty-eight verses of the Veda-stuti are to be considered the essence of all Vedic knowledge. The four Kumāras and all other authorized sages know perfectly that devotional service in Kṛṣṇa consciousness is the essence of all Vedic literature, and they preach this on different planets, traveling in outer space. It is stated herein that such sages, including Nārada Muni, hardly ever travel on land; they perpetually travel in space.
Sages like Nārada and the Kumāras travel throughout the universe to educate the conditioned souls that their business in the world is not that of sense gratification but of reinstating themselves in their original position of devotional service to the Supreme Personality of Godhead. It is stated in several places that the living entities are like sparks of the fire and the Supreme Personality of Godhead is like the fire itself. If the sparks somehow or other fall out of the fire, they lose their natural illumination; thus it is ascertained that the living entities come into this material world exactly as sparks fall from a great fire. The living entity wants to imitate Kṛṣṇa and tries to lord it over material nature in order to enjoy sense gratification; thus he forgets his original position, and his illuminating power, his spiritual identity, is extinguished. However, if a living entity takes to Kṛṣṇa consciousness, he is reinstated in his original position. To preach this process of devotional service, sages and saints like Nārada and the Kumāras travel all over the universe educating people and increasing their disciples. Their aim is that all the conditioned souls may be educated to revive their original consciousness, or Kṛṣṇa consciousness, and thus gain relief from the miserable conditions of material life.
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.