The soul is eternally indestructible and immeasurable; accept this through authorized Vedic knowledge, not material experimentation.Listen — Srila Prabhupada Uvaca
Bhagavad-gītā 2.18 — August 24, 1973, London 730824BG-LONDON [30:10 Minutes] Bg-02.18_730824BG-LONDON Pradyumna: [leads chanting of verse] [Prabhupāda and devotees repeat] antavanta ime dehā nityasyoktāḥ śarīriṇaḥ anāśino 'prameyasya tasmād yudhyasva bhārata [Bg. 2.18] [break] [00:23] Translation: "Only the material body of the indestructible, immeasurable and eternal living entity is subject to destruction; therefore fight, O descendant of Bharata." Prabhupāda: Antavanta ime dehā nityasyoktāḥ śarīriṇaḥ. Śarīriṇaḥ, This is plural number. Śarīriṇ. So śarīrin or śarīrī means the proprietor of the śarīra, or body. Śarīra means this body, and śarīrin, one who possesses the body. So plural number is śarīriṇaḥ. In a varieties of ways, Kṛṣṇa is convincing Arjuna that the soul is different from this body.
So this body, antavat: it will be finished. However you may try, so scientifically, applying cosmetic and other things, you cannot save the body. That is not possible. Antavat.
Anta means..., antavat means..., anta means end, and vat means possessing. So "You have got your duty to fight, and you are lamenting that the body of your grandfather or teacher or kinsmen, they'll be destroyed and you will be unhappy. That's all right, you'll be unhappy, but even if you do not fight, their body will be finished today or tomorrow or say a few years after. So why should you go back from discharging your duty?" This is the point.
"And so far the soul is concerned, of your grandfather, teacher and others, they are nitya, eternal." Already explained. Nityasya uktāḥ. Now Kṛṣṇa here also says ukta. Ukta means "it is said." Not that dogmatically I am speaking, I am putting up some theory. No.
It is said. It is already settled, it is already ascertained. And in the Vedic literature, by authorities it is so said. This is the way of presenting evidence.
Even Kṛṣṇa, the Supreme Personality of Godhead, He does not theorize. He said, "It is said," authorized. Anāśino 'prameyasya. Anāśinaḥ.
Nāśinaḥ means destructible, and anāśinaḥ means not destructible. Śarīriṇaḥ, the soul, anāśinaḥ, it will never be destroyed. And aprameyasya. Aprameyasya, immeasurable. It cannot be measured also.