"In Vrajabhumi there is the Yamuna River with its sandy banks. There are kadamba trees, cows, Krsna's sticks with which He herds cows, and Krsna's flute. All of these belong to the santa-rasa, the mellow of neutrality in devotional service."
"By the grace of the Lord, ...the spiritual consciousness of every species of life can occupy its proper place, and these species can express their spiritual affection for the Lord in the santa-rasa, as displayed by the land, water, hills, trees, fruits, and flowers of Vrndavana during the presence of Lord Sri Krsna, the Personality of Godhead. The Lord reciprocated the feelings of the inhabitants of the forest of Vrndavana. When there was rainfall, the Lord took shelter at the feet of the trees or in the caves and enjoyed the taste of different fruits with his eternal associates the cowherd boys."
When one is completely free from all doubts and material attachments, he attains the neutral position called santa-rati, or santa-rasa. The santa-rati realization of Krsna is in the neutral stage between the conception of impersonalism and personalism. This means that one is not very strongly attached to the personal feature of the Lord. An appreciation of the greatness of the Lord is called santa-rati. This is attachment not to the personal feature but to the impersonal feature. Generally, one in this stage is attached to the Paramatma feature of the Supreme Personality of Godhead. In the santa-rasa, a devotee sees the Lord's representation everywhere.
The specific characteristics of santa-rasa - unflinching faith in Krsna and cessation of all desires which are not connected with Krsna - are common to all other rasas as well, just as sound is generally present in all other elements (air, fire, water and earth) because it is produced from the sky. Similarly, these two characteristics of santa-rasa are present in other transcendental relationships, such as dasya (servitorship), sakhya (fraternity), vatsalya (paternal affection), and the madhura-rasa (conjugal love).
Although there is attachment for Krsna in awe and veneration in the santa-rasa along with these two valuable transcendental qualities - attachment for Krsna and detachment from material desires - nonetheless the sense of intimacy is lacking.
By that intimacy one thinks of Krsna as one's only shelter and only friend. In the santa-rasa one accepts Krsna as the impersonal Param Brahma or the localized Paramatma. This is based on the speculative knowledge of the jnani. However, when this knowledge is further developed, one is convinced that Paramatma, the Supreme Lord, is master and that the living entity is His eternal servant. One then attains the platform of dasya-rasa.
Examples of santa-bhaktas, or devotees in the neutral stage, are the nine yogis named Kavi, Havi, Antariksa, Prabuddha, Pippalayana, Avirhotra, Dravida or Drumila, Camasa and Karabhajana. The four Kumaras (Sanaka, Sanandana, Sanatkumara and Sanatana) are also examples of this stage.
"Neutrality can be further subdivided into general, transparent and peaceful. An attraction for Krsna by the people in general or by children cannot take any specific or satisfactory position. It can be manifest sometimes in trembling of the body and changing of the color of the eyes (to red, white, etc.), although there is no symptom of any particular affection.
One old man was told by a young man, “Just see how this child-only three years old-is so jubilant! Simply by seeing Krsna he is running so swiftly, making a tumultuous sound. Just see!” This is an instance of neutral ecstatic love in the heart of a child, without any specific subdivision.
Due to the different types of attraction for Krsna, there are different varieties of devotees. Their symptoms are manifested transparently, just like jewels. It is said that a great devotee brahmana would sometimes address the Supreme Personality of Godhead as master and sometimes joke with the Lord, using different kinds of familiar words. Sometimes he would protect the Lord with a filial affection, sometimes he would cry out to the Lord, addressing the Lord as his beloved, and sometimes he would meditate on the Lord as the Supersoul. This means that the brahmana expressed his ecstatic loving symptoms in different ways at different times. But in each instance, because of ecstatic love, the brahmana merged himself in the ocean of happiness and became situated in pure love. Thus he was a transparent medium, like a jewel that shows reality in varying colors according to its own nature.
When the great sage Narada was glorifying the pastimes of the Lord with his vina, the four Kumaras, headed by Sanaka, although merged in the impersonal conception of Brahman, were trembling all over. Another devotee once exclaimed, “Although I can achieve liberation simply by serving the devotees, my mind is still very much anxious to see the Supreme Personality of Godhead, whose bodily complexion is just like a dark cloud.” When a devotee is so anxious to contact the Supreme Personality of Godhead, that can also be accepted as a symptom of neutral love."
Nectar of Devotion, Chapter 32
Bhaktivedanta Book Trust. HDG A.C. Bhaktivedanta Swami Srila Prabhupada.