The gross body is a product of the subtle body. As stated in Bhagavad-gītā (8.6):
yaṁ yaṁ vāpi smaran bhāvaṁ
tyajaty ante kalevaram
taṁ tam evaiti kaunteya
sadā tad-bhāva-bhāvitaḥ
"Whatever state of being one remembers when he quits his body, that state he will attain without fail." The atmosphere of the subtle body at the time of death is created by the activities of the gross body. Thus the gross body acts during one's lifetime, and the subtle body acts at the time of death. The subtle body, which is called liṅga, the body of desire, is the background for the development of a particular type of gross body, which is either like that of one's mother or like that of one's father. According to the Ṛg Veda, if at the time of sex the secretions of the mother are more profuse than those of the father, the child will receive a female body, and if the secretions of the father are more profuse than those of the mother, the child will receive a male body. These are the subtle laws of nature, which act according to the desire of the living entity. If a human being is taught to change his subtle body by developing a consciousness of Kṛṣṇa, at the time of death the subtle body will create a gross body in which he will be a devotee of Kṛṣṇa, or if he is still more perfect, he will not take another material body but will immediately get a spiritual body and thus return home, back to Godhead. This is the process of the transmigration of the soul. Therefore instead of trying to unite human society through pacts for sense gratification that can never be achieved, it is clearly desirable to teach people how to become Kṛṣṇa conscious and return home, back to Godhead. This is true now and, indeed, at any time.
(Srimad Bhagavatam----6:1:54----purport).

As confirmed in Bhagavad-gītā (4.9), janma karma ca me divyam evaṁ yo vetti tattvataḥ: one must simply understand the Supreme Person, Kṛṣṇa, in terms of His form, name, activities and pastimes. This will keep one always in the association of Kṛṣṇa. Tyaktvā dehaṁ punar janma naiti mām eti so'rjuna: thus after giving up his gross material body, one accepts not another gross body but a spiritual body in which to return home, back to Godhead. Thus one ends the tribulation caused by his association with the material energy. In summary, the living entity is an eternal servant of God, but he comes to the material world and is bound by material conditions because of his desire to lord it over matter.
(Srimad Bhagavatam----6:1:55----purport).

If one is favored by the Supreme Personality of Godhead by having his gross body touched by the Lord, his body turns into a spiritual body, and he can go back home, back to Godhead. Gajendra assumed a spiritual body when his body was touched by the Lord. Similarly, Dhruva Mahārāja assumed his spiritual body in this way. Arcanā-paddhati, daily worship of the Deity, provides an opportunity to touch the body of the Supreme Personality of Godhead, and thus it enables one to be fortunate enough to get a spiritual body and go back to Godhead. Not only by touching the body of the Supreme Lord, but simply by hearing about His pastimes, chanting His glories, touching His feet and offering worship—in other words, by serving the Lord somehow or other—one is purified of material contamination. This is the result of touching the Supreme Lord. One who is a pure devotee (anyābhilāṣitā-śūnyam (Bhakti-rasāmṛta-sindhu 1.1.11)), who acts according to the śāstra and the words of the Supreme Personality of Godhead, certainly becomes purified. Like Gajendra, he assumes a spiritual body and returns home, back to Godhead.
(Srimad Bhagavatam----8:4:6----purport).

This is the process of the soul's transmigration from one body to another. At the time of death, according to his mental condition, the living being is carried by the subtle body, consisting of mind, intelligence and ego, to another gross body. When higher authorities have decided what kind of gross body the living entity will have, he is forced to enter such a body, and thus he automatically gives up his previous body. Dull-minded persons who do not have the intelligence to understand this process of transmigration take for granted that when the gross body is finished, one's life is finished forever.
(Srimad Bhagavatam----10:1:40----purport).

Meanwhile, because of the Lord's presence within the womb of Devakī, all the demigods came to offer the Lord their prayers. The Supreme Personality of Godhead, they said, is eternally the Absolute Truth. The spiritual soul is more important than the gross body, and the Supersoul, Paramātmā, is still more important than the soul. The Supreme Godhead is absolutely independent, and His incarnations are transcendental.
(Srimad Bhagavatam----10:2--summary).

Realization of the viśuddha-sattva platform is beyond the pale of the material world and is not perceived by bodily senses or mental speculation. Our identification with the gross body and subtle mind is different from spiritual understanding. Since the intelligence and mind are material, the loving affairs of Śrī Rādhā and Kṛṣṇa are beyond their perception.
(Sri Caitanya Caritamrta----2:8:193----purport).

The spiritual senses are beyond the material senses. A materialist can think only of the negation of material variety; he cannot understand spiritual variety. He thinks that spiritual variety simply contradicts material variety and is a negation or void, but such conceptions cannot even reach the precincts of spiritual realization. The wonderful activities of the gross body and subtle mind are always imperfect. They are below the degree of spiritual understanding and are ephemeral.
(Sri Caitanya Caritamrta----2:8:193----purport).

When one is situated in his spiritual body, which is beyond this gross and subtle material body, he is fit to serve Rādhā and Kṛṣṇa. That body is called siddha-deha. The living entity attains a particular type of gross body in accordance with his past activities and mental condition. In this life the mental condition changes in different ways, and the same living entity gets another body in the next life according to his desires. The mind, intelligence and false ego are always engaged in an attempt to dominate material nature. According to that subtle astral body, one attains a gross body to enjoy the objects of one's desires. According to the activities of the present body, one prepares another subtle body. And according to the subtle body, one attains another gross body. This is the process of material existence. However, when one is spiritually situated and does not desire a gross or subtle body, he attains his original spiritual body. As confirmed by the Bhagavad-gītā (4.9): tyaktvā dehaṁ punar janma naiti mām eti so ’rjuna.
(Sri Caitanya Caritamrta----2:8:229----purport).

Due to the conditioned soul's eternal attitude of separation from Kṛṣṇa, the spell of material energy awards him two kinds of bodily existence—the gross body consisting of five elements, and the subtle body consisting of mind, intelligence and ego. Being covered by these two bodies, the conditioned soul eternally suffers the pangs of material existence known as the threefold miseries. He is also subjected to six enemies (such as lust, anger, etc.). Such is the everlasting disease of the conditioned soul.
(Teachings of Lord Caitanya).

This exchange of feelings between Kṛṣṇa and Rādhārāṇī is very difficult to understand unless one is elevated to the platform of pure goodness. Such transcendental reciprocation is not even possible to understand from the platform of material goodness. One has to actually transcend material goodness in order to understand. This is because the exchange of feelings between Rādhā and Kṛṣṇa is not a subject matter of this material world. Even the greatest mental speculator cannot understand this, directly or indirectly. Material activities are manifested either for the gross body or the subtle mind, but this exchange of feelings between Rādhā and Kṛṣṇa is beyond such manifestations and beyond intellectual mental speculation. It can only be understood by purified senses freed from all the designations of the material world. Those who have purified senses can understand these transcendental features and exchanges, but those who are impersonalists and who have no knowledge of spiritual senses can only discriminate within the scope of the material senses and thus cannot understand spiritual exchanges or spiritual-sensual activities.
(Teachings of Lord Caitanya).