Ramanuja's Gita Bhashyam - Chapter 2 - sloka 18

The entire content of this mail is based  on  Swami Adidevananda's translation of  Sri Ramanuja Gita Bhashya, published by Sri Ramakrishna Math.

The Real and the Unreal Sloka 16-20

1 Gita Sloka every day - Chapter 2 - Samkhya Yoga - Sloka 18

Anta vantah ime deha nityasya uktah sharirinah I

Anashinah aprameyasya tasmat yudhyasva bharata II sloka 18

अन्त वन्तः इमे देहाःनित्यस्य उक्ताः शरीरिणः ।

अनाशिनः अप्रमेयस्य तस्मात युध्यस्व भारत ।। श्लोक १८ 

These bodies of the Jiva (the embodied self), are said to have an end while the Jiva itself is eternal, indestructible and incomprehensible. Therefore fight, O Bharata (Arjuna)

The root "dih"  means to grow. Hence these bodies (Dehas) are characterised  by complexity. They have an end - their nature is perishability. For, jugs and such other things which are characterised by complexity are seen to have an end. The bodies of the embodied self, which are made of conglomerated elements, serve the purpose of experiencing the effects of karmas as stated in Brh.U.IV.4.5 - "Auspicious embodiments are got through good actions". Such bodies perish when karmas are exhausted. Further the self is imperishable. Why? because it is not measurable. Neither can It be conceived as the object of knowledge,  but only asof a single the subject (knower). Later in 13.1, it is taught : "He who knows It is called the knower of the Field by those who know this".

Besides the self is not seen to be made up of many (elements). Because in the perception "I am the knower" throughout the body, only something other than the body is understood as possessing an invariable from as the knower. Further, this knower cannot be dismembered and seen in different places as is the case with the body. Therefore the self is eternal. For

(i) It is not a complex being  of a single form

(ii) It serves the purpose of experiencing the fruits of karma by the embodied self

(iii) It has a plurality of parts and 

(iv) It can be pervaded.

Therefore, as the body is by nature perishable and the self by nature is eternal, both are not objects fit for grief. Hence, bearing with courage the inevitable strike of weapons, sharp or hard, liable to be received by you and others, begin the action called war without being attached to the fruits but for the sake of attaining immortality.