Chapter2- Sloka 33
atha-cet tvam imaṃ dharmyaṃ saṇgrāmaṃ |
tataḥ sva-dharmaṃ kīrtiṃ ca hitvā pāpam avāpsyasi || 33 ||
(2.33)
atha- However if; tvam- you; na kariṣyasi cet- do not fight; imaṃ dharmyaṃ saṇgrāmaṃ- this righteous war; tataḥ- then; hitvā- (you will be) turning away from; sva-dharmaṃ- performance of your class based (varṇa based) duty; kīrtiṃ ca- and your reputation; avāpsyasi- (and) will be incurring; pāpam- sin;
Purport
In ślokas 2.31 and 2.32 Kṛṣṇa explained to Arjuna that since this war is dharma compliant, it is surely a means to his mokṣa. In this śloka and the next one, Kṛṣṇa explains to Arjuna about the consequences he will face if he does not fight this righteous war. Kṛṣṇa says, "If however, you do not fight this righteous war then you will be turning away from the performance of your duty as a warrior and your reputation too and you will be incurring sin."
atha (If However) With these words Kṛṣṇa means to say that, 'Instead of following my advice that you should fight this war, if you choose to go with your own opinion that you should not fight this war.
tvam (you) Kṛṣṇa means to say, 'O Arjuna! You are not a brāhmana but a kṣatriya'. (Brāhmana varṇa is the learned class who learn and teach vedas and śāstras. Kṣatriya varṇa is the warrior class)
imaṃ dharmyaṃ saṇgrāmaṃ 'It does not befit you to skip your duty as a kṣatriya. If the war had not begun, it was still ok to not start it. But the war has already begun...
na kariṣyasi cet (Perceiving this righteous war as unrighteous, if you abstain from fighting this war which has already begun...) The consequences of this inaction are told now.
tataḥ (then) When Arjuna, an able warrior, does not lead this righteous war ahead but chooses to back off even after it has started.
sva-dharmaṃ hitvā The first part of the śloka talks about the scenario of giving up the kṣatriya duty. This part talks about the consequences of giving up his duty. Hence the term 'dharma' here refers to the result of dharma (fruit of the action and not the action itself). Therefore, the meaning is that, 'If you do not fight the war, you will lose the benefit of mokṣa after this lifetime, which is the highest objective of human pursuit.
kīrtiṃ ca hitvā (You will lose the great fame and glory that victory in this war will fetch you in this lifetime) If Arjuna does not fight the war, he will lose this fame and glory too.
pāpam avāpsyasi Arjuna will not just forego the benefits of this lifetime and the future, but also incur sin which will result in the experience of great sorrow in the next lifetime.