The living being, by his desiring to lord it over the material world and declining to cooperate with the Supreme Lord, contacts the sum total of the material world, namely the mahat-tattva, and from the mahat-tattva his false identity with the material world, intelligence, mind and senses is developed. This covers his pure spiritual identity. By the yogic process, when his pure identity is realized in self-realization, one has to revert to the original position by amalgamating the five gross elements and the subtle elements, mind and intelligence, into the mahat-tattva again. Thus getting freed from the clutches of the mahat-tattva, he has to merge in the existence of the Supersoul. In other words, he has to realize that qualitatively he is nondifferent from the Supersoul, and thus he transcends the material sky by his pure identical intelligence and thus becomes engaged in the transcendental loving service of the Lord. This is the highest perfectional development of spiritual identity, which was attained by Dhṛtarāṣṭra by the grace of Vidura and the Lord. The Lord's mercy was bestowed upon him by his personal contact with Vidura, and when he was actually practicing the instructions of Vidura, the Lord helped him to attain the highest perfectional stage.
(Srimad Bhagavatam----1:13:55----purport).

The functions of the mind are thinking, feeling and willing. When the mind is materialistic, or absorbed in material contact, it acts for material advancement of knowledge, destructively ending in discovery of nuclear weapons. But when the mind acts under spiritual urge, it acts wonderfully for going back home, back to Godhead, for life in complete bliss and eternity. Therefore the mind has to be manipulated by good and unalloyed intelligence. Perfect intelligence is to render service unto the Lord. One should be intelligent enough to understand that the living being is, in all circumstances, a servant of the circumstances. Every living being is serving the dictates of desire, anger, lust, illusion, insanity and enviousness—all materially affected. But even while executing such dictations of different temperaments, he is perpetually unhappy. When one actually feels this and turns his intelligence to inquiring about it from the right sources, he gets information of the transcendental loving service of the Lord. Instead of serving materially for the abovementioned different humors of the body, the living entity's intelligence then becomes freed from the unhappy illusion of materialistic temperament, and thus, by unalloyed intelligence, the mind is brought into the service of the Lord. The Lord and His service are identical, being on the absolute plane. Therefore the unalloyed intelligence and the mind are merged into the Lord, and thus the living entity does not remain a seer himself but becomes seen by the Lord transcendentally. When the living entity is directly seen by the Lord, the Lord dictates to him to act according to His desire, and when the living entity follows Him perfectly, the living entity ceases to discharge any other duty for his illusory satisfaction. In his pure unalloyed state, the living being attains the stage of full bliss, labdhopaśānti, and ceases all material hankerings.
(Srimad Bhagavatam----2:2:16----purport).

The mystic yogīs, after a strenuous effort to control the senses, may be situated in a trance of yoga just to have a vision of the Supersoul within everyone, but the pure devotee, simply by remembering the Lord's lotus feet at every second, at once becomes established in real trance because by such realization his mind and intelligence are completely cleansed of the diseases of material enjoyment. The pure devotee thinks himself fallen into the ocean of birth and death and incessantly prays to the Lord to lift him up. He only aspires to become a speck of transcendental dust at the lotus feet of the Lord. The pure devotee, by the grace of the Lord, absolutely loses all attraction for material enjoyment, and to keep free from contamination he always thinks of the lotus feet of the Lord.
(Srimad Bhagavatam----2:4:21----purport).

This phenomenal world is impersonally the representation of Vāsudeva because the ingredients of its creation, their interaction and the enjoyer of the resultant action, the living being, are all produced by the external and internal energies of Lord Kṛṣṇa. This is confirmed in the Bhagavad-gītā (7.4-5). The ingredients, namely earth, water, fire, air and sky, as well as the conception of material identity, intelligence and the mind, are produced of the external energy of the Lord. The living entity who enjoys the interaction of the above gross and subtle ingredients, as set up by eternal time, is an offshoot of internal potency, with freedom to remain either in the material world or in the spiritual world. In the material world the living entity is enticed by deluding nescience, but in the spiritual world he is in the normal condition of spiritual existence without any delusion. The living entity is known as the marginal potency of the Lord. But in all circumstances, neither the material ingredients nor the spiritual parts and parcels are independent of the Personality of Godhead Vāsudeva, for all things, whether products of the external, internal or marginal potencies of the Lord, are simply displays of the same effulgence of the Lord, just as light, heat and smoke are displays of fire. None of them are separate from the fire—all of them combine together to be called fire; similarly, all phenomenal manifestations, as well as the effulgence of the body of Vāsudeva, are His impersonal features, whereas He eternally exists in His transcendental form called sac-cid-ānanda-vigrahaḥ (Bs. 5.1), distinct from all conceptions of the material ingredients mentioned above.
(Srimad Bhagavatam----2:5:14----purport).

In order to explain the ten divisional symptoms of the Śrīmad-Bhāgavatam, there are seven continuous verses. The first of these under reference pertains to the sixteen elementary manifestations of earth, water, etc., with material ego composed of material intelligence and mind. The subsequent creation is a result of the reactions of the above-mentioned sixteen energies of the first puruṣa, the Mahā-Viṣṇu incarnation of Govinda, as later explained by Brahmā in his treatise Brahma-saṁhitā (5.47) as follows:
yaḥ kāraṇārṇava-jale bhajati sma yoga-
nidrām ananta-jagad-aṇḍa-sa-roma-kūpaḥ
ādhāra-śaktim avalambya parāṁ sva-mūrtiṁ
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
The first puruṣa incarnation of Govinda, Lord Kṛṣṇa, known as the Mahā-Viṣṇu, goes into a yoga-nidrā mystic sleep, and the innumerable universes are situated in potency in each and every hair hole of His transcendental body.
(Srimad Bhagavatam----2:10:3----purport).

It has been explained in the previous verses that mind is the product of ego in goodness and that the function of the mind is acceptance and rejection according to desire. But here intelligence is said to be the product of ego in passion. That is the distinction between mind and intelligence; mind is a product of egoism in goodness, and intelligence is a product of egoism in passion. The desire to accept something and reject something is a very important factor of the mind. Since mind is a product of the mode of goodness, if it is fixed upon the Lord of the mind, Aniruddha, then the mind can be changed to Kṛṣṇa consciousness. It is stated by Narottama dāsa Ṭhākura that we always have desires. Desire cannot be stopped. But if we transfer our desires to please the Supreme Personality of Godhead, that is the perfection of life. As soon as the desire is transferred to lording it over material nature, it becomes contaminated by matter. Desire has to be purified. In the beginning, this purification process has to be carried out by the order of the spiritual master, since the spiritual master knows how the disciple's desires can be transformed into Kṛṣṇa consciousness. As far as intelligence is concerned, it is clearly stated here that it is a product of egoism in passion. By practice one comes to the point of the mode of goodness, and by surrendering or fixing the mind upon the Supreme Personality of Godhead, one becomes a very great personality, or mahātmā. In Bhagavad-gītā it is clearly said, sa mahātmā sudurlabhaḥ: "Such a great soul is very rare."
(Srimad Bhagavatam----3:26:31----purport).

When one is detached from the attraction of material prosperity, one can actually concentrate his mind upon the Supersoul. As long as the mind is distracted towards the material, there is no possibility of concentrating one's mind and intelligence upon the Supreme Personality of Godhead or His partial representation, Supersoul. In other words, one cannot concentrate one's mind and energy upon the Supreme unless one is detached from the material world. Following detachment from the material world, one can actually attain transcendental knowledge of the Absolute Truth. As long as one is entangled in sense enjoyment, or material enjoyment, it is not possible to understand the Absolute Truth. This is also confirmed in Bhagavad-gītā (18.54). One who is freed from material contamination is joyful and can enter into devotional service, and by devotional service he can be liberated.
(Srimad Bhagavatam----3:26:72----purport).

The explanation by Rūpa Gosvāmī in the Bhakti-rasāmṛta-sindhu of how a person can be liberated even in this body is more elaborately explained in this verse. The living entity who has become satya-dṛk, who realizes his position in relationship with the Supreme Personality of Godhead, may remain apparently merged in the five elements of matter, the five material sense objects, the ten senses and the mind and intelligence, but still he is considered to be awake and to be freed from the reaction of false ego. Here the word līna is very significant. The Māyāvādī philosophers recommend merging in the impersonal effulgence of Brahman; that is their ultimate goal, or destination. That merging is also mentioned here. But in spite of merging, one can keep his individuality. The example given by Jīva Gosvāmī is that a green bird that enters a green tree appears to merge in the color of greenness, but actually the bird does not lose its individuality. Similarly, a living entity merged either in the material nature or in the spiritual nature does not give up his individuality. Real individuality is to understand oneself to be the eternal servitor of the Supreme Lord. This information is received from the mouth of Lord Caitanya. He said clearly, upon the inquiry of Sanātana Gosvāmī, that a living entity is the servitor of Kṛṣṇa eternally. Kṛṣṇa also confirms in Bhagavad-gītā that the living entity is eternally His part and parcel. The part and parcel is meant to serve the whole. This is individuality. It is so even in this material existence, when the living entity apparently merges in matter. His gross body is made up of five elements, his subtle body is made of mind, intelligence, false ego and contaminated consciousness, and he has five active senses and five knowledge-acquiring senses. In this way he merges in matter. But even while merged in the twenty-four elements of matter, he can keep his individuality as the eternal servitor of the Lord. Either in the spiritual nature or in the material nature, such a servitor is to be considered a liberated soul. That is the explanation of the authorities, and it is confirmed in this verse.
(Srimad Bhagavatam----3:27:14----purport).

Anyone can become successful in devotional service provided he displays no duplicity. It is explained here that one must be very frank and open-minded (amāyinaḥ). To be situated in a lower status of life is not a disqualification for success in devotional service. The only qualification is that whether one is a brāhmaṇa, kṣatriya, vaiśya or śūdra, he must be open, frank and free from reservations. Then, by performing his particular occupational duty under the guidance of a proper spiritual master, he can achieve the highest success in life. As confirmed by the Lord Himself, striyo vaiśyās tathā śūdrās te 'pi yānti parāṁ gatim (B.G.9:32). It does not matter what one is, whether a brāhmaṇa, kṣatriya, vaiśya, śūdra or a degraded woman. If one engages himself seriously in devotional service, working with body, mind and intelligence, he is sure to be successful in going back home, back to Godhead. The Lord's lotus feet are described here as kāma-dughāṅghri-paṅkajam because they have all power to fulfill the desires of everyone. A devotee is happy even in this life because although in material existence we have many needs, all his material needs are satisfied, and when he at last quits his body, he goes back home, back to Godhead, without a doubt.
(Srimad Bhagavatam----4:21:33----purport).

The mind and intelligence of the living entity in material existence are affected by the modes of material nature, and according to the association of the material modes, the mind is habituated to go here and there. The heart feels satisfaction, jubilation or illusion according to the effects of the modes of material nature. Actually the living entity in his material condition remains inert. It is the modes of material nature that act on the mind and heart. The results are enjoyed or suffered by the living entity. This is clearly stated in Bhagavad-gītā (3.27):
prakṛteḥ kriyamāṇāni
guṇaiḥ karmāṇi sarvaśaḥ
ahaṅkāra-vimūḍhātmā
kartāham iti manyate
"The bewildered spirit soul, under the influence of the three modes of material nature, thinks himself the doer of activities that are in actuality carried out by nature."
(Srimad Bhagavatam----4:29:16----purport).

The desires in the subtle body of mind, intelligence and ego cannot be fulfilled without a gross body composed of the material elements earth, water, air, fire and ether. When the gross material body is not manifest, the living entity cannot factually act in the modes of material nature. In this verse it is clearly explained that the subtle activities of themind and intelligence continue due to the sufferings and enjoyments of the living entity's subtle body. The consciousness of material identification (such as "I" and "mine") still continues because such consciousness has been extant from time immemorial. However, when one transfers to the spiritual world by virtue of understanding Kṛṣṇa consciousness, the actions and reactions of both gross and subtle bodies no longer bother the spirit soul.
(Srimad Bhagavatam----4:29:70----purport).

"The Supreme Personality of Godhead, the Supersoul, Lord Hari, is the controller of both the living entities and the material nature. He is self-sufficient and self-effulgent. As the subject matter of perception is not the cause of our perceiving senses, so the living entity, although within his body, does not cause his eternal friend the Supersoul, who is the cause of creation of all the senses. Because of the living entity's ignorance, his senses are engaged with material objects. Since the living entity is alive, he can understand the creation of this material world to some extent, but he cannot understand the Supreme Personality of Godhead, who is beyond the conception of the body, mind and intelligence. Nevertheless, great sages who are always in meditation can see the personal form of the Lord within their hearts."
(Srimad Bhagavatam----6:4--summary).

Human society should be divided into a social system of brāhmaṇas, kṣatriyas, vaiśyas and śūdras, but everyone can engage in devotional service. If one wants to live without devotional service, his status as a brāhmaṇa, kṣatriya, vaiśya or śūdra certainly has no meaning. It is said, sthānād bhraṣṭāḥ patanty adhaḥ: whether one is in a higher or lower division, one certainly falls down for want of Kṛṣṇa consciousness. A sane man, therefore, is always fearful of falling from his position. This is a regulative principle. One should not fall from his exalted position. The highest goal of life can be achieved as long as one's body is stout and strong. We should therefore live in such a way that we keep ourselves always healthy and strong in mind and intelligence so that we can distinguish the goal of life from a life full of problems. A thoughtful man must act in this way, learning to distinguish right from wrong, and thus attain the goal of life.
(Srimad Bhagavatam----7:6:5----purport).