Since the mind may be one’s enemy or one’s friend, one has to train the mind to become his friend. The Kṛṣṇa consciousness movement is especially meant for training the mind to be always engaged in Kṛṣṇa’s business. The mind contains hundreds and thousands of impressions, not only of this life but also of many, many lives of the past. These impressions sometimes come in contact with one another and produce contradictory pictures. In this way the mind’s function can become dangerous for a conditioned soul. Students of psychology are aware of the mind’s various psychological changes. In Bhagavad-gītā (8.6) it is said:

yaṁ yaṁ vāpi smaran bhāvaṁ
tyajaty ante kalevaram
taṁ taṁ evaiti kaunteya
sadā tad-bhāva-bhāvitaḥ

“Whatever state of being one remembers when he quits his body, that state he will attain without fail.”

At the time of death, the mind and intelligence of a living entity create the subtle form of a certain type of body for the next life. If the mind suddenly thinks of something not very congenial, one has to take a corresponding birth in the next life. On the other hand, if one can think of Kṛṣṇa at the time of death, he can be transferred to the spiritual world, Goloka Vṛndāvana. This process of transmigration is very subtle; therefore Śrīla Rūpa Gosvāmī advises devotees to train their minds in order that they will be unable to remember anything other than Kṛṣṇa. Similarly, the tongue should be trained to speak only of Kṛṣṇa and to taste only kṛṣṇa-prasāda. Śrīla Rūpa Gosvāmī further advises, tiṣṭhan vraje: one should live in Vṛndāvana or any part of Vrajabhūmi. Vrajabhūmi, or the land of Vṛndāvana, is supposed to be eighty-four krośas in area. One krośa equals two square miles. When one makes Vṛndāvana his residence, he should take shelter of an advanced devotee there. In this way one should always think of Kṛṣṇa and His pastimes. This is further elucidated by Śrīla Rūpa Gosvāmī in his Bhakti-rasāmṛta-sindhu (1.2.294):

kṛṣṇaṁ smaran janaṁ cāsya
preṣṭhaṁ nija-samīhitam
tat-tat-kathā-rataś cāsau
kuryād vāsaṁ vraje sadā

“A devotee should always reside in the transcendental realm of Vraja and always engage in kṛṣṇaṁ smaran janaṁ cāsya preṣṭham, the remembrance of Śrī Kṛṣṇa and His beloved associates. By following in the footsteps of such associates and by entering under their eternal guidance, one can acquire an intense desire to serve the Supreme Personality of Godhead.”

Again Śrīla Rūpa Gosvāmī states in Bhakti-rasāmṛta-sindhu (1.2.295):

sevā sādhaka-rūpeṇa
siddha-rūpeṇa cātra hi
tad-bhāva-lipsunā kāryā
vraja-lokānusārataḥ

“In the transcendental realm of Vraja [Vraja-dhāma] one should serve the Supreme Lord, Śrī Kṛṣṇa, with a feeling similar to that of His associates, and one should place himself under the direct guidance of a particular associate of Kṛṣṇa and should follow in his footsteps. This method is applicable both in the stage of sādhana [spiritual practices executed while in the stage of bondage] and in the stage of sādhya [God realization], when one is a siddha-puruṣa, or a spiritually perfect soul.”

Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura has commented as follows upon this verse: “One who has not yet developed interest in Kṛṣṇa consciousness should give up all material motives and train his mind by following the progressive regulative principles, namely chanting and remembering Kṛṣṇa and His name, form, quality, pastimes and so forth. In this way, after developing a taste for such things, one should try to live in Vṛndāvana and pass his time constantly remembering Kṛṣṇa’s name, fame, pastimes and qualities under the direction and protection of an expert devotee. This is the sum and substance of all instruction regarding the cultivation of devotional service.

“In the neophyte stage one should always engage in hearing kṛṣṇa-kathā. This is called śravaṇa-daśā, the stage of hearing. By constantly hearing the transcendental holy name of Kṛṣṇa and hearing of His transcendental form, qualities and pastimes, one can attain to the stage of acceptance called varaṇa-daśā. When one attains this stage, he becomes attached to the hearing of kṛṣṇa-kathā. When one is able to chant in ecstasy, he attains the stage of smaraṇāvasthā, the stage of remembering. Recollection, absorption, meditation, constant remembrance and trance are the five items of progressive kṛṣṇa-smaraṇa. At first, remembrance of Kṛṣṇa may be interrupted at intervals, but later remembrance proceeds uninterrupted. When remembrance is uninterrupted, it becomes concentrated and is called meditation. When meditation expands and becomes constant, it is called anusmṛti. By uninterrupted and unceasing anusmṛti one enters the stage of samādhi, or spiritual trance. After smaraṇa-daśā or samādhi has fully developed, the soul comes to understand his original constitutional position. At that time he can perfectly and clearly understand his eternal relationship with Kṛṣṇa. That is called sampatti-daśā, the perfection of life.

“Caitanya-caritāmṛta advises those who are neophytes to give up all kinds of motivated desires and simply engage in the regulative devotional service of the Lord according to the directions of scripture. In this way a neophyte can gradually develop attachment for Kṛṣṇa’s name, fame, form, qualities and so forth. When one has developed such attachment, he can spontaneously serve the lotus feet of Kṛṣṇa even without following the regulative principles. This stage is called rāga-bhakti, or devotional service in spontaneous love. At that stage the devotee can follow in the footsteps of one of the eternal associates of Kṛṣṇa in Vṛndāvana. This is called rāgānuga-bhakti. Rāgānuga-bhakti, or spontaneous devotional service, can be executed in the śānta-rasa when one aspires to be like Kṛṣṇa’s cows or the stick or flute in the hand of Kṛṣṇa, or the flowers around Kṛṣṇa’s neck. In the dāsya-rasa one follows in the footsteps of servants like Citraka, Patraka or Raktaka. In the friendly sakhya-rasa one can become a friend like Baladeva, Śrīdāmā or Sudāmā. In the vātsalya-rasa, characterized by parental affection, one can become like Nanda Mahārāja and Yaśodā, and in the mādhurya-rasa, characterized by conjugal love, one can become like Śrīmatī Rādhārāṇī or Her lady friends such as Lalitā and Her serving maids (mañjarīs) like Rūpa and Rati. This is the essence of all instruction in the matter of devotional service.”