In Śrīmad-Bhāgavatam, Third Canto, it is explained that under the control of superior authority a living entity is put within the semen of a male and injected into the womb of a particular female in order to develop a particular type of body. A living entity utilizes his senses, intelligence, mind and so on in a specific way of his own choosing and thus develops a particular type of body, within which he becomes encaged. In this way the living entity becomes situated in different species of life, either in a demigod, human or animal body, according to different situations and circumstances.
It is explained in the Vedic literature that the living entities entrapped in different species of life are part and parcel of the Supreme Lord. The Māyāvādī philosophers mistake the living entity for the Paramātmā, who is actually sitting with the living entity as a friend. Because the Paramātmā (the localized aspect of the Supreme Personality of Godhead) and the individual living entity are both within the body, a misunderstanding sometimes takes place that there is no difference between the two. But there is a definite difference between the individual soul and the Supersoul, and it is explained in the Varāha Purāṇa as follows. The Supreme Lord has two kinds of parts and parcels: the living entity is called vibhinnāṁśa, and the Paramātmā, or the plenary expansion of the Supreme Lord, is called svāṁśa. The svāṁśa plenary expansion of the Supreme Personality is as powerful as the Supreme Personality of Godhead Himself. There is not even the slightest difference between the potency of the Supreme Person and that of His plenary expansion as Paramātmā. But the vibhinnāṁśa parts and parcels possess only a minute portion of the potencies of the Lord. The Nārada Pañcarātra states that the living entities, who are the marginal potency of the Supreme Lord, are undoubtedly of the same quality of spiritual existence as the Lord Himself, but they are prone to be tinged with the material qualities. Because the minute living entity is prone to be subjected to the influence of material qualities, he is called jīva, and sometimes the Supreme Personality of Godhead is also known as Śiva, the all-auspicious one. So the difference between Śiva and jīva is that the all-auspicious Personality of Godhead is never affected by the material qualities whereas the minute portions of the Supreme Personality of Godhead are prone to be affected by the qualities of material nature.
The Supersoul within the body of a particular living entity, being a plenary portion of the Lord, is worshipable by the individual living entity. Great sages have therefore concluded that the process of meditation is designed so that the individual living entity may concentrate his attention on the lotus feet of the Supersoul form (Viṣṇu). That is real samādhi. The living entity cannot be liberated from material entanglement by his own effort. He must therefore take to the devotional service of the lotus feet of the Supreme Lord, or the Supersoul within himself. Śrīdhara Svāmī, the great commentator on Śrīmad-Bhāgavatam, has composed a nice verse in this regard, the meaning of which is as follows: "My dear Lord, I am eternally a part of You, but I have been entrapped by the material potencies, which are also an emanation from You. As the cause of all causes, You have entered my body as the Supersoul, and I have the prerogative of enjoying the supreme blissful life of knowledge along with You. Therefore, my dear Lord, please order me to render You loving service so that I can again be brought to my original position of transcendental bliss."
Great personalities understand that a living entity entangled in this material world cannot be freed by his own efforts. With firm faith and devotion, such great personalities engage themselves in rendering transcendental loving service to the Lord. That is the verdict of the personified Vedas.
The personified Vedas continued: "Dear Lord, it is very difficult to achieve perfect knowledge of the Absolute Truth. Your Lordship is so kind to the fallen souls that You appear in different incarnations and execute different activities. You appear even as a historical personality of this material world, and Your pastimes are very nicely described in the Vedic literature. Such pastimes are as attractive as the ocean of transcendental bliss. People in general have a natural inclination to read narrations in which ordinary jīvas are glorified, but when they become attracted by the Vedic scriptures which delineate Your eternal pastimes, they actually dip into the ocean of transcendental bliss. As a fatigued man feels refreshed by dipping into a reservoir of water, so the conditioned soul who is very much disgusted with material activities becomes refreshed and forgets all the fatigue of material activities simply by dipping into the transcendental ocean of Your pastimes. And eventually he merges into the ocean of transcendental bliss. The most intelligent devotees, therefore, do not take to any means of self-realization except devotional service and constant engagement in the nine different processes of devotional life, especially hearing and chanting. When hearing and chanting about Your transcendental pastimes, Your devotees do not care even for the transcendental bliss derived from liberation or from merging into the existence of the Supreme. Such devotees are not interested even in so-called liberation, and they certainly have no interest in material activities for elevation to the heavenly planets for sense gratification. Pure devotees seek only the association of paramahaṁsas, or great liberated devotees, so that they can continuously hear and chant about Your glories. For this purpose the pure devotees are prepared to sacrifice all comforts of life, even giving up the material comforts of family life and so-called society, friendship and love. Those who have tasted the nectar of devotion by relishing the transcendental vibration of chanting Your glories—Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare / Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare—do not care for any other spiritual bliss or for material comforts, which appear to the pure devotee as less important than the straw in the street."
The personified Vedas continued: “Dear Lord, when a person is able to purify his mind, senses and intelligence by engaging himself in devotional service in full Kṛṣṇa consciousness, his mind becomes his friend. Otherwise, his mind is always his enemy. When the mind is engaged in the devotional service of the Lord, it becomes the intimate friend of the living entity because the mind can then think of the Supreme Lord always. Your Lordship is eternally dear to the living entity, so when the mind is engaged in thought of You one immediately feels the great satisfaction for which he has been hankering life after life. When one's mind is thus fixed on the lotus feet of the Supreme Personality of Godhead, one does not take to any kind of inferior worship or inferior process of self-realization. By attempting to worship a demigod or by taking to any other process of self-realization, the living entity becomes a victim of the cycle of birth and death, and no one can estimate how much the living entity is degraded by entering abominable species of life such as cats and dogs.”
Śrī Narottama dāsa Ṭhākura has sung that persons who do not take to the devotional service of the Lord but are attracted to the process of philosophical speculation and fruitive activities drink the poisonous results of such actions. Such persons eat all kinds of obnoxious things, such as meat, and take pleasure in alcohol and other intoxicants, and after death they are forced to take birth in lower species of life. Materialistic persons generally worship the transient material body and forget the welfare of the spirit soul within the body. Some take shelter of materialistic science to improve bodily comforts, and some take to the worship of demigods to be promoted to the heavenly planets. Their goal in life is to make the material body comfortable, but they forget the interest of the spirit soul. Such persons are described in the Vedic literature as suicidal, because attachment for the material body and its comforts forces the living entity to wander through the process of birth and death perpetually and suffer the material pangs as a matter of course. The human form of life is a chance for one to understand his position. Therefore the most intelligent person takes to devotional service just to engage his mind, senses and body in the service of the Lord without deviation.
The personified Vedas continued: "Dear Lord, there are many mystic yogīs who are very learned and deliberate in achieving the highest perfection of life. They engage themselves in the yogic process of controlling the life air within the body. Concentrating the mind upon the form of Viṣṇu and controlling the senses very rigidly, they practice the yoga system, but even after much laborious austerity, penance and regulation, they achieve the same destination as persons inimical toward You. In other words, both the yogīs and the great, wise philosophical speculators ultimately attain the impersonal Brahman effulgence, which is automatically attained by the demons who are regular enemies of the Lord. Demons like Kaṁsa, Śiśupāla and Dantavakra attain the Brahman effulgence because they constantly meditate upon the Supreme Personality of Godhead out of enmity. The real point is to concentrate the mind on the Supreme Personality of Godhead. Women such as the gopīs were attached to Kṛṣṇa, being captivated by His beauty, and their mental concentration on Kṛṣṇa was provoked by lust. They wanted to be embraced by the arms of Kṛṣṇa, which resemble the beautiful round shape of a snake. Similarly, we, the Vedic hymns, simply concentrate our minds on the lotus feet of Your Lordship. Women like the gopīs concentrate upon You under the dictation of lust, and we concentrate upon Your lotus feet to go back home, back to Godhead. Your enemies also concentrate upon You, thinking always of how to kill You, and yogīs undertake great penances and austerities just to attain Your impersonal effulgence. All these different persons, although concentrating their minds in different ways, achieve spiritual perfection according to their different perspectives because You, O Lord, are equal to all Your devotees."
Śrīdhara Svāmī has composed a nice verse in this regard: "My dear Lord, to be engaged always in thinking of Your lotus feet is very difficult. It is possible for great devotees who have already achieved love for You and are engaged in transcendental loving service. My dear Lord, I wish that my mind may also be fixed somehow or other on Your lotus feet, at least for some time."
The attainment of spiritual perfection by different spiritualists is explained in the Bhagavad-gītā, wherein the Lord says that He grants the perfection the devotee desires in proportion to the devotee's surrender unto Him. The impersonalists, yogīs and enemies of the Lord enter into the Lord's transcendental effulgence, but the personalists who follow in the footsteps of the inhabitants of Vṛndāvana or strictly follow the path of devotional service are elevated to the personal abode of Kṛṣṇa, Goloka Vṛndāvana, or to the Vaikuṇṭha planets. Both the impersonalists and the personalists enter the spiritual realm, the spiritual sky, but the impersonalists are given their place in the impersonal Brahman effulgence, whereas the personalists are given a position in the Vaikuṇṭha planets or in the Vṛndāvana planet, according to their desire to serve the Lord in different mellows.
The personified Vedas stated that persons born after the creation of this material world cannot understand the existence of the Supreme Personality of Godhead by manipulating their material knowledge. Just as a person born in a particular family cannot understand the position of his great-grandfather, who lived before the birth of the recent generation, we are unable to understand the Supreme Personality of Godhead, Nārāyaṇa, or Kṛṣṇa, who exists eternally in the spiritual world. In the Eighth Chapter of the Bhagavad-gītā it is clearly said that the Supreme Person, who lives eternally in the spiritual kingdom of God (sanātana-dhāma), can be approached only by devotional service.