Holding pleasure and pain, gain and loss, victory and defeat as equal, then prepare yourself for battle. In this way you will not incur sin.
Explanation
Krishna is advising Arjuna, who hesitates to fight. He asks Arjuna to meet pleasure and pain, gain and loss, victory and defeat with the same even mind (samatā), and to fight as his duty (dharma). Acting from this balance, not from desire for results, is why no sin (pāpa) attaches to him. This prepares the teaching of karma yoga, the discipline of selfless action, in the next verses.