Bhagavad Gita 2.48

योगस्थ: कुरु कर्माणि सङ्गं त्यक्त्वा धनञ्जय |
सिद्ध्यसिद्ध्यो: समो भूत्वा समत्वं योग उच्यते

Translation

Be steadfast in the performance of your duty, O Arjun, abandoning attachment to success and failure. Such equanimity is called Yog.