Link:-Arjuna was grieved, by apprehending the death of his kinsmen and preceptors. Moreover he was afraid that sin would accrue to him, by killing them and that sin would lead him to hell. Therefore Lord Krsna preached this gospel in the eleventh to the thirtieth verses. Now, He starts the worldly standpoint and reminds Arjuna of his duty, as a member of the warrior class.
svadharmamapi caveksya na vikampitumarhasi
dharmyaddhi yuddhacchreyo'nyatksatriyasya na vidyate
Looking at your own duty as well, you should not falter for there is, nothing more meritorious to a person of the warrior class (Ksatriya) than a righteous war. 31
[In the first two verses, He describes the benefit of war.]
Svadharmamapi caveksya na vikampitumarhasi:-Man (soul) is a fragment of God. But by identifying himself with the body, noting himself as a Brahmana (of the priest class) or a Ksatriya (of the warrior class) etc., he has to discharge his duty as a member of that class. Similarly one who acknowledging himself as a teacher or a father, has to discharge the duty of a teacher or a father.
Here, the duty of a Ksatriya has been called 'Dharma' (righteousness). It is the foremost duty of a Ksatriya not to flee from war front. For a Ksatriya, righteousness is upheld by waging war. So, Lord Krsna asks Arjuna to discharge his duty, by waging war. He should never shirk that duty.
Dharmyaddhi yuddhacchreyo'nyatkxatriyasya na vidyate:-There is nothing more welcome to a man of the warrior class than a righteous war viz., which is his main duty (Gita 18/43). Similar, is the case with, the people of other classes—the priest, the business and the labour classes.
Arjuna, in the seventh verse of the second chapter, requested Lord Krsna to tell him what is good for him. In response to his request, Lord Krsna tells him, that he would attain salvation by performing his duty of waging a righteous war. So, he should not retreat from it.