2-48

योगस्थः कुरु कर्माणि सङ्गम् त्यक्त्वा धनन्जय ।
सिद्ध्यसिद्ध्योः समो भूत्वा समत्वम् योग उच्यते ॥ ४८ ॥

yogasthaH kuru karmANi saGgam tyaktvA dhananjaya |
siddhyasiddhyoH samo bhUtvA samatvam yoga ucyate || 48 ||

धनन्जय [dhananjaya] Arjuna, कर्माणि कुरु [karmANi kuru] do your activity योगस्थः [yogasthaH] situated in yoga. सङ्गम् त्यज्त्वा [saGgam tyajtvA] Giving up attachments, सिद्ध्यसुद्ध्योः समो भूत्वा [siddhyasuddhyoH samo bhUtvA] having the same attitude towards success and failure. समत्वम् [samatvam] This kind of equanimity योग उच्यते [yoga ucyate] is called yoga.

Involve in activities like this war while being situated in yoga. Give up attachment towards the kingdom, your relatives and other things. Consider success - like a victory in battle and any failure in achievement as being equal.

Here, the consideration that success and failure are equal is called yoga. Yoga is impassioned thought. When you consider success and failure to be equal, you are ‘situated in yoga’.

Next, He explains why this is emphasized so many times.