Dr. Singh. Must the spirit soul necessarily have a body—either spiritual or material?
Śrīla Prabhupāda. The soul already has a spiritual body, which the material body covers. My material body grows upon me—my spiritual body—but my material body is unnatural. The real body is spiritual. I am accepting various bodies that are unnatural to my constitution. My real, constitutional position is to be the servant of Kṛṣṇa. As long as I do not come to that position, I remain a servant of matter and get many material bodies according to the laws of material energy. i get one body and then give it up. I desire something else and again get another body. This process is going on under the strict laws of material nature. People think they completely control their destinies, but they are always under nature’s law of karma:
guṇaiḥ karmāṇi sarvaśaḥ
kartāham iti manyate
“The bewildered spirit soul, under the influence of the three modes of material nature, thinks himself to be the doer of activities that are In actuality carried out by nature.”
(Bhagavad-gītā As It Is 3.27)
The source of this bewilderment is that the living entity thinks, “I am this body.”
hṛd-deśe ‘rjuna tiṣṭhati
(Bhagavad-gītā As It Is 18.61)
In this verse the word yantra, or “machine,” means that in any species of life, we are traveling in bodies that are like machines provided by material nature. Sometimes we are moving to higher species, sometimes to lower species. But if, by the mercy of the spiritual master and Kṛṣṇa, one gets the seed of devotional service and cultivates it, he can become free from the cycle of birth and death. Then his life is successful. Otherwise, he has to travel up and down the different species of life, becoming sometimes a blade of grass, sometimes a lion, and so forth.
Source:Life Comes from Life
(His Divine Grace A.C. Bhaktivedanta Swami Prabhupada)