Bhagavad Gita 2.48
Revised: Perform all your actions with your mind concentrated on the Divine, renouncing attachment and looking upon success and failure with an equal eye. Spirituality implies equanimity.
योगस्थः कुरु कर्माणि सङ्गं त्यक्त्वा धनञ्जय।
सिद्ध्यसिद्ध्योः समो भूत्वा समत्वं योग उच्यते॥yogasthaḥ kuru karmāṇi saṅgaṃ tyaktvā dhanañjaya|
siddhyasiddhyoḥ samo bhūtvā samatvaṃ yoga ucyate||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).