On the bank of the Daśāśvamedha-ghāṭa at Prayāga for ten days continually the Lord instructed Rūpa Gosvāmī in the science of devotional service to the Lord. He taught the Gosvāmī the divisions of the living creatures in the 8,400,000 species of life. Then He taught him about the human species. Out of them He discussed the followers of the Vedic principles, out of them the fruitive workers, out of them the empiric philosophers, and out of them the liberated souls. He said that there are only a few who are actually pure devotees of Lord Śrī Kṛṣṇa.
Śrīla Rūpa Gosvāmī was the younger brother of Sanātana Gosvāmī, and when he retired from service he brought with him two boat fulls of gold coins. This means that he brought with him some hundreds of thousands of rupees accumulated by the labor of his service. And before leaving home for Lord Caitanya Mahāprabhu, he divided the wealth as follows: fifty percent for the service of the Lord and His devotees, twenty-five percent for relatives and twenty-five percent for his personal needs in case of emergency. In that way he set an example for all householders.
The Lord taught the Gosvāmī about devotional service, comparing it to a creeper, and advised him to protect the bhakti creeper most carefully against the mad elephant offense against the pure devotees. In addition, the creeper has to be protected from the desires of sense enjoyment, monistic liberation and perfection of the haṭha-yoga system. They are all detrimental on the path of devotional service. Similarly, violence against living beings, and desire for worldly gain, worldly reception and worldly fame are all detrimental to the progress of bhakti, or Bhāgavata-dharma.
Pure devotional service must be freed from all desires for sense gratification, fruitive aspirations and culture of monistic knowledge. One must be freed from all kinds of designations, and when one is thus converted to transcendental purity, one can then serve the Lord by purified senses.
As long as there is the desire to enjoy sensually or to become one with the Supreme or to possess the mystic powers, there is no question of attaining the stage of pure devotional service.
Devotional service is conducted under two categories, namely primary practice and spontaneous emotion. When one can rise to the platform of spontaneous emotion, he can make further progress by spiritual attachment, feeling, love, and many higher stages of devotional life for which there are no English words. We have tried to explain the science of devotional service in our book The Nectar of Devotion, based on the authority of Bhakti-rasāmṛta-sindhu by Śrīla Rūpa Gosvāmī.