Krishna explains about swa-dharmam (2.31-2.37), Para-dharmam (other's nature) (3.35) and finally advises shunning all Dharmas (18.66) to unite with Paramatma .
Arjun’s despondency arose out of his egocentric fear of damaging his reputation if he fought the war and killed his brethren. Krishna tells him (2.34-2.36) that he would damage his reputation even if he avoided battle, as fighting is his swa-dharmam . The community would feel that Arjuna was fearful of engaging in battle and for a Kshatriya fearing battle is worse than death.
Krishna further explains (3.35) that, swa-dharmam , even if it's faulty or devoid of merits, is better than para-dharmam and death in the path of swa-dharmam is better than para-dharmam , which is fraught with fear.
Para-dharmam is perceived as easy and better by our outward looking senses, especially when we observe successful people, whereas Swa-dharmam requires discipline and hard work and needs to be slowly uncovered in us. Ordinarily, our sense of self-worth comes, among other things, from being favourably compared, the prestigious place/ family where we are born, grades in the school, good earnings in a job or profession and power/fame that comes our way. But for Krishna, everyone is unique and would blossom uniquely as per his Swa-dharmam. He says that while the unmanifest in all is the same, each manifested entity is unique.
Finally, Krishna advises(18.66) us to shun all Dharmas and take refuge in him for he would then liberate us from all sins. This is akin to surrender in Bhakti Yoga and is one of the foundations of spirituality.
Just as a river loses its swa-dharmam of meandering on becoming a part of the ocean, we too should lose ahankaar and swa-dharmam to unite with paramatma.
Source - Daily World