SB 10.1.43

jyotir yathaivodaka-pārthiveṣv adaḥ
 samīra-vegānugataṁ vibhāvyate
evaṁ sva-māyā-raciteṣv asau pumān
 guṇeṣu rāgānugato vimuhyati
Word for word: 
jyotiḥ — the luminaries in the sky, such as the sun, the moon and the stars; yathā — as; eva — indeed; udaka — in water; pārthiveṣu — or in other liquids, like oil; adaḥ — directly; samīra-vega-anugatam — being forced by the movements of the wind; vibhāvyate — appear in different shapes; evam — in this way; sva-māyā-raciteṣu — in the situation created by one’s mental concoctions; asau — the living entity; pumān — person; guṇeṣu — in the material world, manifested by the modes of nature; rāga-anugataḥ — according to his attachment; vimuhyati — becomes bewildered by identification.
Translation: 
When the luminaries in the sky, such as the moon, the sun and the stars, are reflected in liquids like oil or water, they appear to be of different shapes — sometimes round, sometimes long, and so on — because of the movements of the wind. Similarly, when the living entity, the soul, is absorbed in materialistic thoughts, he accepts various manifestations as his own identity because of ignorance. In other words, one is bewildered by mental concoctions because of agitation from the material modes of nature.
Purport: 

This verse gives a very good example by which to understand the different positions of the eternal spiritual soul in the material world and how the soul takes on different bodies (dehāntara-prāptiḥ). The moon is stationary and is one, but when it is reflected in water or oil, it appears to take different shapes because of the movements of the wind. Similarly, the soul is the eternal servant of Kṛṣṇa, the Supreme Personality of Godhead, but when put into the material modes of nature, it takes different bodies, sometimes as a demigod, sometimes a man, a dog, a tree and so on. By the influence of māyā, the illusory potency of the Supreme Personality of Godhead, the living entity thinks that he is this person, that person, American, Indian, cat, dog, tree or whatever. This is called māyā. When one is freed from this bewilderment and understands that the soul does not belong to any shape of this material world, one is situated on the spiritual platform (brahma-bhūta).

This realization is sometimes explained as nirākāra, or formlessness. This formlessness, however, does not mean that the soul has no form. The soul has form, but the external, agitating form he has acquired because of material contamination is false. Similarly, God is also described as nirākāra, which means that God has no material form but is sac-cid-ānanda-vigraha. The living entity is part and parcel of the supreme sac-cid-ānanda-vigraha, but his material forms are temporary, or illusory. Both the living entity and the Supreme Lord have original, spiritual forms (sac-cid-ānanda-vigraha), but the Lord, the Supreme, does not change His form. The Lord appears as He is, whereas the living entity appears because material nature forces him to accept different forms. When the living entity receives these different forms, he identifies with them, and not with his original, spiritual form. As soon as the living entity returns to his original, spiritual form and understanding, he immediately surrenders to the supreme form, the Personality of Godhead. This is explained in Bhagavad-gītā (7.19). Bahūnāṁ janmanām ante jñānavān māṁ prapadyate. When the living entity, after many, many births in different forms, returns to his original form of Kṛṣṇa consciousness, he immediately surrenders unto the lotus feet of the supreme form, Kṛṣṇa. This is liberation. As the Lord says in Bhagavad-gītā (18.54):

brahma-bhūtaḥ prasannātmā
 na śocati na kāṅkṣati
samaḥ sarveṣu bhūteṣu
 mad-bhaktiṁ labhate parām

“One who is thus transcendentally situated at once realizes the Supreme Brahman and becomes fully joyful. He never laments nor desires to have anything; he is equally disposed to every living entity. In that state he attains pure devotional service unto Me.” Surrender unto the supreme form is the result of bhakti. This bhakti, or understanding of one’s own position, is the complete liberation. As long as one is under an impersonal understanding of the Absolute Truth, he is not in pure knowledge, but must still struggle for pure knowledge. Kleśo ’dhikataras teṣām avyaktāsakta-cetasām (Bg. 12.5). Although one may be spiritually advanced, if one is attached to the impersonal feature of the Absolute Truth one must still work very hard, as indicated by the words kleśo ’dhikataraḥ, which mean “greater suffering.” A devotee, however, easily attains his original position as a spiritual form and understands the Supreme Personality of Godhead in His original form.

Kṛṣṇa Himself explains the forms of the living entities in the Second Chapter of Bhagavad-gītā, where He clearly says to Arjuna that He, Arjuna and all other living entities, who were previously in their original forms, are separate individual identities. They were individuals in the past, they are now situated in individuality, and in the future they will all continue to maintain their individual forms. The only difference is that the conditioned living entity appears in various material forms, whereas Kṛṣṇa appears in His original, spiritual form. Unfortunately, those who are not advanced in spiritual knowledge think that Kṛṣṇa is like one of them and that His form is like their material forms. Avajānanti māṁ mūḍhā mānuṣīṁ tanum āśritam (Bg. 9.11). Kṛṣṇa is never puffed up by material knowledge and is therefore called acyuta, whereas the living entities fall down and are agitated by material nature. This is the difference between the Supreme Lord and the living entities.

In this connection it is to be noted that Vasudeva, who was situated in a transcendental position, advised Kaṁsa not to commit further sinful activities. Kaṁsa, a representative of the demons, was always ready to kill Kṛṣṇa, or God, whereas Vasudeva represents a transcendentally situated person to whom Kṛṣṇa is born (Vāsudeva is the son of Vasudeva). Vasudeva wanted his brother-in-law Kaṁsa to refrain from the sinful act of killing his sister, since the result of being agitated by material nature would be that Kaṁsa would have to accept a body in which to suffer again and again. Elsewhere in Śrīmad-Bhāgavatam (5.5.4), Ṛṣabhadeva also says:

na sādhu manye yata ātmano ’yam
 asann api kleśada āsa dehaḥ

As long as the living entity is entangled in the fruitive activities of so-called happiness and distress, he will receive a particular type of body in which to endure the three kinds of suffering due to material nature (tri-tāpa-yantraṇā). An intelligent person, therefore, must free himself from the influence of the three modes of material nature and revive his original, spiritual body by engaging in the service of the Supreme Person, Kṛṣṇa. As long as one is materially attached, one must accept the process of birth, death, old age and disease. One is therefore advised that an intelligent person, instead of being entangled in so-called good and bad fruitive activities, should engage his life in advancing in Kṛṣṇa consciousness so that instead of accepting another material body (tyaktvā dehaṁ punar janma naiti), he will return home, back to Godhead.