This soul is the part and Parcel of Godhead
Every living entity being the part and parcel of the Supreme Godhead it is quite unnatural that they should live in this material world. The living entity’s struggle for existence in the material world is a wrong struggle because the spirit soul cannot by happy by any amount of material pleasures. The basic principle of present day civilization is to enjoy and exploit the material world at the highest possible degree. That is a wrong civilization. The fifteenth chapter of Bhagwat Geeta denounces this tendency of material civilization. This material civilization is compared there with a banyan tree which has its root upwards and branches and leaves downwards. The highest plane of this universe is known as the ‘Brahmaloka’ wherein lives the creator of this universe namely Brahma. Brahma being the root of this creation other lower planes which are called Jana, Tapa, Swarga, Bhuba and Bhuloka are but different branches of the tree going downwards. Those who know nothing except struggling hard for existence cannot know also the beginning or end of this banyan tree of universe.
The branches of this tree are spread all over the universe according to the modes of Nature. The three modes of nature namely goodness, passion and ignorance are the three dominating principles of Nature. As such those (souls) who are in the mode of goodness are found as powerful gods, those who are in the mode of passion are found to be powerful worker [omission] of the world and those who are in the mode of ignorance are found as uncivilized brutes, animals and similar lower grade forms of life. So the spirit soul is moving all over the tree without knowing how to get rid of the tangle of the tree. The speculators or the empiric philosophers may go on speculating in a speed like that of the wind or the mind and that for millions of years together, still they cannot know where is the beginning or end of the universe. If therefore the living entity wants to get free from the entanglement of this huge banyan tree he has to learn the tact from Bhagwat Geeta. The root of the tree has to be cut down by the sharpened weapon of non-affection. The real [omission] is he therefore who has surpassed the affection for this material world. Paid philosopher can only speculate but they cannot show us the way to get out. If therefore any body wishes to return to the kingdom of God the right place of happiness for the soul proper, one has to surrender unto Him from whom everything has emanated. And by returning to Him nobody has to come back again in this unhappy material world. The primary qualification for entering into the kingdom of God is to shun in the very beginning variety material knowledge to be one from the illusion of material civilization. Some persons can only transcend the affection of worldly pleasure and happiness and are therefore liberated persons. They can only understand in full knowledge how to [omission] from the false struggle for existence and they can survive only as the fittest persons.
The kingdom of God, as we can know from Bhagwat Geet, is not illuminated by the sun or moon like this material
world. The kingdom is self-illuminated and whoever shall go there can enjoy ever increasing happiness. The soul when he, mistakably, [omission] himself as the product of the material elements he is at once in bondage of the modes of nature. But as soon as he realises his own self as spirit he at once enters into the kingdom of God even in his present tabernacle. The affect for material pleasure is the root cause of material consciousness. One has to learn therefore the spiritual art for not being affected by material pleasure. The highest and grossest type of material pleasure is sexuality and one who has become to control the sexual appetite is on the road to the kingdom of God.
Therefore the living entity although he is part and parcel of Godhead, he is thrown into material existence due to his desire to enjoy the material world by his material and the sense organs.
It is the desire for material enjoyment that carries the soul from one body to another. It is mistake to think that the soul after his so called death i.e. after giving up this material body when it is unworkable, the soul is made liberated. He carries his desire with him after leaving this body and as the air carries the flavor good or bad so the soul carries with him the flavor of his present desire to another body. When he gets another body or transmigrates into another material body according to the flavor of his past desires, he develops synthetic body with suitable ears, eyes, hands, tongue, nose and other sense organs in 84 lakhs of life so that he can enjoy the material world according to his developed desires. It is therefore the desires that we have to rectify in order to enter into the kingdom of God. Those who want to enter into the kingdom of God can do so without any difficulty and those who do not went to enter there may remain here in this material world perpetually. That is the position of the soul proper. The foolish persons only do not desire to enter into the kingdom of God because they are so dumb that repeated miseries of the material world cannot bring them any good sense. Because such foolish persons are devoid of sight transcendental they cannot see to the threefold miseries of the material world.
The ‘yogis’ especially the ‘Bhaktayogias’ can understand the real position of the soul and therefore they do try to know further about it. But yogis who take to the process for some material gain are impure souls and by their yogic process they can improve their material position only without entering into the kingdom of spirit.
The gross materialists shall argue that they have no information of the kingdom of God and therefore they have no interest for it. But still they cannot explain the sun, the moon or the fire that illuminate the material world. The material world by constitution is dark. It is the sun, moon or the fire that illuminates it. And any sane man even among the gross materialists will I surely know that the light that comes from the sun, moon or fire are only rays of spiritualism. That is what is explained in the Bhagwat Geeta. The power that hangs the huge planets explained away by material scientist as law of gravitation but it is the sample of spiritualism. The power that generates the potency of [omission] in contact with the rays of the moon, is also spiritualism. The power that dominates in the stomach for digesting all kinds of food and drink is also spiritualism. Thus the spiritualism or the internal potency of Godhead is overcast all over the material world and the gross materialist (who under the external potency of God) may take hints from all these what is the kingdom of God and how He works. Unless Godhead would not have lived in the heart of every living body, the soul would fail to do work according to his past desire by remembrance. After the annihilation of the body of the soul, it forgets all about his past life. But it is Godhead only who makes him able to do according to his past desires. So Godhead is not only all pervading impersonal Brahma but He is also localised Godhead or Paramatma within the heart of all living entities. The personality of Godhead or the Purshotam is the primeval case of Brahma, Paramatma, and the individual soul and one who knows Him, knows everything well.

Link to this page:

If you Love Me Distribute My Books -- Srila Prabhupada