|Chapter 2: Contents of the Gita Summarized|
sukha-duhkhe same kritva
tato yuddhaya yujyasva
naivam papam avapsyasi
Do thou fight for the sake of fighting, without considering happiness or distress, loss or gain, victory or defeat — and by so doing you shall never incur sin.
This is an important verse because Krishna here combines the two seemingly contradictory approaches that He had given to Arjuna. Earlier (2.11-2.30) Krishna had asked Arjuna to fight based on jnana – the knowledge that the body is distinct from the soul. Later (2.31-37) Krishna asked Arjuna to fight since in doing so he will get material enjoyment and avoid sinful reactions, which is karma-kanda. Now Krishna asks Arjuna to "fight for the sake of fighting," which means he should fight as it is his duty to do so. He also asks him to fight "without considering happiness or distress, loss or gain, victory or defeat." Such a consideration comes to one who is in knowledge of the body and the spirit and thus detached from the results of any material activity. Combining these two, Krishna now instructs Arjuna to fight (karma) with detachment (jnana). This is called buddhi-yoga or niskama-karma-yoga which is detached work on the platform of knowledge. Because there is detachment to the result of the work, there are no reactions, good or bad to the work performed. Niskama-karma yoga could be performed simply on the platform of jnana (which gives material detachment) or bhakti (in which attachment to Krishna automatically gives material detachment and is therefore by far superior). Srila Prabhupada gives us an early sneek preview of this, "He who acts for his own sense gratification, either in goodness or in passion, is subject to the reaction, good or bad. But he who has completely surrendered himself in the activities of Krishna consciousness is no longer obliged to anyone, nor is he a debtor to anyone, as one is in the ordinary course of activities." In the next 15 verses (2.39-2.53) Krishna expands on this concept of buddhi yoga that He introduced in this verse.
Please read the Sanskrit Verse and the Prabhupada's Purport.