Bhagavad Gita 2.33

अथ चेत्तत्त्विमं धर्म्यम्बतं न करिष्यसि |
तत: स्वधर्मं कीर्तिं च हित्वा पापमवाप्स्यसि

Translation

If, however, you refuse to fight this righteous war, abandoning your social duty and reputation, you will certainly incur sin.