Bhagavad Gita · Sankhya YogaChapter 2, Shloka 18 (2.18)
Original Sanskrit · श्रीभगवान्
अन्तवन्त इमे देहा नित्यस्योक्ताः शरीरिणः
अनाशिनोऽप्रमेयस्य तस्माद् युध्यस्व भारत
॥ 2.18 ॥
antavanta ime dehā nityasyoktāḥ śarīriṇaḥ
anāśino'prameyasya tasmād yudhyasva bhārata
Translation
"These bodies of the eternal, imperishable and immeasurable (not measurable by any means of knowledge) embodied one (the self) are said to be perishable. Therefore, O Bharata, fight."
Interpretation
The body — perishable; the self — three qualities. Three words for the self: nitya (ever-existing), anāśin (imperishable), aprameya (immeasurable). Shankaracharya explains that "nitya" and "anāśin" are not a repetition: in the world "destruction" is of two kinds — (1) disappearing completely (like a body turning to ash), (2) changing form (like falling ill). The self is free of both. And "anāśin" is said along with "nitya" so that no one takes the self to be "relatively eternal" like the earth and so on.
"Aprameya" — the knower, not the known. Ramanuja's beautiful explanation: the self is not known like an object; it is experienced as the knower. He quotes 13.1 — "one who knows this (field) is called the knower of the field".
"Tasmād yudhyasva" — therefore fight. This is the first command of the teaching. Note: Krishna is not saying "the self is eternal, so violence is fine". Arjuna's grief rested on the false belief that his people would be destroyed. Once that belief is removed, no ground for grief remains to stop him from doing his duty — which is the duty of a warrior in a righteous war.
AI-assisted draft translation — under review.