The Yoga of Liberation by Renunciation

Krishna teaches the importance of performing one's own duty. 'Sve sve karmaṇy abhirataḥ saṁsiddhiṁ labhate naraḥ'—a person (naraḥ) attains (labhate) perfection (saṁsiddhim) by being devoted (abhirataḥ) to one's own duty (sve sve karmaṇi). 'Svakarma-nirataḥ siddhiṁ yathā vindati tac chṛṇu'—hear (śṛṇu) how (yathā) one devoted (nirataḥ) to one's own duty (svakarma) attains (vindati) perfection (siddhim). This is the key teaching: perfection comes not from performing someone else's duty, but from being fully devoted to your own duty, according to your nature. When you perform your own duty with devotion, you attain perfection. This sets up the detailed explanation of how performing one's own duty leads to perfection.