Verse 2.48

योगस्थः कुरु कर्माणि सङ्गं त्यक्त्वा धनञ्जय। सिद्ध्यसिद्ध्योः समो भूत्वा समत्वं योग उच्यते।।2.48।।

yoga-sthaḥ kuru karmāṇi saṅgaṁ tyaktvā dhanañjaya siddhy-asiddhyoḥ samo bhūtvā samatvaṁ yoga uchyate

Meaning

Arjun, my guy, stay yoked into yoga, ditch the attachment drama, and keep it even-keeled win or lose. That's what yoga's all about.

Commentary

Yo, Arjun, chill with the Divine, do your thing for the man upstairs, stay balanced whether you win or lose. That's yoga, my dude. Success? That's knowing yourself, getting that pure heart through selfless acts. Failure? Nah, that's when you're all about the rewards, not the self-knowledge. (See 3.9, 4.14, 4.20 for more deets).