This very small spiritual spark is the basic principle of the material body, and the influence of such a spiritual spark is spread all over the body as the influence of the active principle of some medicine spreads throughout the body. This current of the spirit soul is felt all over the body as consciousness, and that is the proof of the presence of the soul. Any layman can understand that the material body minus consciousness is a dead body, and this consciousness cannot be revived in the body by any means of material administration. Therefore, consciousness is not due to any amount of material combination, but to the spirit soul. In the Muṇḍaka Upaniṣad (3.1.9) the measurement of the atomic spirit soul is further explained:
eṣo 'ṇur ātmā cetasā veditavyo
yasmin prāṇaḥ pañcadhā saṁviveśa
prāṇaiś cittaṁ sarvam otaṁ prajānāṁ
yasmin viśuddhe vibhavaty eṣa ātmā
"The soul is atomic in size and can be perceived by perfect intelligence. This atomic soul is floating in the five kinds of air (prāṇa, apāna, vyāna, samāna and udāna), is situated within the heart, and spreads its influence all over the body of the embodied living entities. When the soul is purified from the contamination of the five kinds of material air, its spiritual influence is exhibited."

The haṭha-yoga system is meant for controlling the five kinds of air encircling the pure soul by different kinds of sitting postures—not for any material profit, but for liberation of the minute soul from the entanglement of the material atmosphere.

(BHAGAVAD-GITA-------2:17-------PURPORT).

As stated in the beginning of the Śrīmad-Bhāgavatam, everything emanates from the ultimate source of the Personality of Godhead; it is therefore understood in this verse that medical science or knowledge in medicine was also inaugurated by the Personality of Godhead in His incarnation Dhanvantari, and thus the knowledge is recorded in the Vedas. The Vedas are the source of all knowledge, and thus knowledge in medical science is also there for the perfect cure of the diseases of the living entity. The embodied living entity is diseased by the very construction of his body. The body is the symbol of diseases. The disease may differ from one variety to another, but disease must be there just as there is birth and death for everyone. So, by the grace of the Personality of Godhead, not only are diseases of the body and mind cured, but also the soul is relieved of the constant repetition of birth and death. The name of the Lord is also called bhavauṣadhi, or the source of curing the disease of material existence.

(SRIMAD BHAGAVATAM--------2:7:1-------PURPORT).

When an embodied living entity is hurt by fatal weapons, it is to be known that the living entity within the body is not killed. The spirit soul is so small that it is impossible to kill him by any material weapon, as will be evident from subsequent verses. Nor is the living entity killable, because of his spiritual constitution. What is killed, or is supposed to be killed, is the body only. This, however, does not at all encourage killing of the body. The Vedic injunction is mā hiṁsyāt sarvā bhūtāni: (B.G.9:4) never commit violence to anyone. Nor does understanding that the living entity is not killed encourage animal slaughter. Killing the body of anyone without authority is abominable and is punishable by the law of the state as well as by the law of the Lord. Arjuna, however, is being engaged in killing for the principle of religion, and not whimsically.

(BHAGAVAD-GITA-------2:19-------PURPORT).

As stated in the last chapter, after suffering different kinds of hellish conditions, a man comes again to the human form of body. The same topic is continued in this chapter. In order to give a particular type of human form to a person who has already suffered hellish life, the soul is transferred to the semen of a man who is just suitable to become his father. During sexual intercourse, the soul is transferred through the semen of the father into the mother's womb in order to produce a particular type of body. This process is applicable to all embodied living entities, but it is especially mentioned for the man who was transferred to the Andha-tāmisra hell. After suffering there, when he who has had many types of hellish bodies, like those of dogs and hogs, is to come again to the human form, he is given the chance to take his birth in the same type of body from which he degraded himself to hell.

(SRIMAD BHAGAVATAM--------3:31:1-------PURPORT).

"O Supreme Eternal! If the embodied living entities were eternal and all-pervading like You, then they would not be under Your control. But if the living entities are accepted as minute energies of Your Lordship, then they are at once subject to Your supreme control. Therefore real liberation entails surrender by the living entities to Your control, and that surrender will make them happy. In that constitutional position only can they be controllers. Therefore, men with limited knowledge who advocate the monistic theory that God and the living entities are equal in all respects are actually guided by a faulty and polluted opinion."
(BHAGAVAD-GITA-------7:5-------PURPORT).

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