BG 2.33
अथ चेत्वमिमं धर्म्यं सङ्ग्रामं न करिष्यसि
ततः स्वधर्मं कीर्तिं च हित्वा पापमवाप्स्यसि
atha cetvamimaṃ dharmyaṃ saṅgrāmaṃ na kariṣyasi
tataḥ svadharmaṃ kīrtiṃ ca hitvā pāpamavāpsyasi
TRANSLATION
But if you do not fight this righteous war, you will be turning away from your duty and honoured position, and will be incurring sin.
PURPORT
If in delusion, you do not wage this war, which has started and which is the duty of a Kshatriya, then, owing to the non-performance of your immediate and incumbent duty, you will lose the immeasurable bliss which is the fruit of discharging your duty and the immeasurable fame which is the fruit of victory. In addition, you will incur extreme sin.