Kesava Kasmiri's Commentary
It should not be presumed that a person abstaining from a negative direction to pursue the ascetic life of non- violence, meditation, virtuousness and self-satisfaction seems superior for worshipping the Supreme Lord. What is therefore the purpose of a warriors duty to perform cruel deeds upon the battlefield in pursuit of victory and self-preservation. Anticipating such a doubt Lord Krishna states it is better to follow ones own duties according to station and rank in life as enjoined by the Vedic scriptures. Because to perform anothers duty is not authorised in the Vedic scriptures and being prohibited is fraught with dangers. According to te scriptural injunction: One who exempts themselves from their prescribed actions as enjoined in the Vedic scriptures, is never qualified to perform the prescribed actions of a higher station. Such actions is prohibited.