Bhagavad Gita 3.35 · Shreyan Svadharmo Vigunahश्रेयान्स्वधर्मो विगुणः परधर्मात्स्वनुष्ठितात्।स्वधर्मे निधनं श्रेयः परधर्मो भयावहः ॥

It is indeed better for man to die discharging his own duty though destitute of merit than for him to live doing the duty of another though performed in a perfect manner. For the duty of another has its pitfalls. The duty of a Kshatriya is to fight in a righteous battle. Arjuna must fight. This is his duty. Even if he dies in the discharge of his own duty, it is better for him. He will go to heaven. He should not do the duty of another man. This will bring him peril. He should not stop from fighting and enter the path of renunciation. (Cf.XVIII.47).