yoga-sthah kuru karmani sangam tyaktva dhananjaya siddhy-asiddhyoh samo bhutva samatvam yoga ucyate
Translation
O Arjuna! Perform your duties being on the path of Yoga leaving behind attachment and remaining even minded in success and failure. Such calm temperament is called Yoga.
Purport
After explaining the principle of Karma Yoga, Bhagvan Shri Krishna explains Arjuna for how to perform actions. Bhagvan tells that a human should perform his action leaving the attachement to the fruits of actions, indirectly saying, for the welfare of the others. One should remain even(equipoised) in both loss and gain.
