Bhagwad Gita
Chapter 2, Verse 33
अथ चैत्त्वमिमं धर्म्यं संग्रामं न करिष्यसि।
ततः स्वधर्मं कीर्तिं च हित्वा पापमवाप्स्यसि।।2.33।।
If you do not fight this important battle, then you will definitely make a mistake by not doing your duty and will lose your good name as a warrior.