Actually, all Vedic culture is aiming at understanding Lord Viṣṇu. In the Ṛg Veda one mantra says that any advanced saintly person is always aspiring to be fixed in meditation upon the lotus feet of Viṣṇu.
In the Śrīmad-Bhāgavatam it is said that the foolish do not know that Viṣṇu is the ultimate goal of life. According to the conclusion of all authoritative Vedic scriptures, when a person comes to the stage of appreciating Viṣṇu, he is at the beginning of devotional service. If one cultivates devotional service further and further, under proper guidance, other features of devotional service will gradually become manifest. At this stage of śānta-rasa, one can see Lord Viṣṇu, the Supreme Personality of Godhead, the deliverer of even the demons. The Lord is appreciated by such would-be devotees as the eternal transcendental form, chief of all self-realized souls, the supersoul, the supreme Brahman, completely pacified, completely controlled and pure, merciful to the devotees and untouched by any material condition. This appreciation of Lord Viṣṇu in awe and veneration by the saintly is to be understood as the sign that they are situated in the śānta-rasa, or neutral stage of devotional service.
This stage of śānta-rasa can be attained by the impersonalists only when they are in association with pure devotees. Otherwise it is not possible. After Brahman realization, when a liberated soul comes in contact with a pure devotee of Lord Kṛṣṇa and submissively accepts the teachings of Lord Kṛṣṇa without misinterpretation, he becomes situated in this neutral stage of devotional service. The best example of saintly persons situated in the śānta-rasa are Sanaka, Sanātana, Sananda, and Sanat-kumāra, the Kumāra brothers. These four saintly persons (known as Catuḥsana) were sons of Lord Brahmā. After their birth, when they were ordered by their father to become householders and increase human society, they refused the order. They said that they had already decided not to become entangled with family life; they would rather live as saintly brahmacārīs for their own perfection. So these great saints have been living for millions of years now, but still they appear to be just like boys of four or five years. Their complexions are very fair, there is an effulgence in their bodies, and they always travel naked. These four saintly persons almost always remain together.