Bhagavad Gita 18.26
But when a person has no sentiment or ego, when they possess courage and confidence, not caring whether they succeed or fail, then their action arises from purity.
मुक्तसङ्गोऽनहंवादी धृत्युत्साहसमन्वितः।सिद्ध्यसिद्ध्योर्निर्विकारः कर्ता सात्त्विक उच्यते॥muktasaṅgo'nahaṃvādī dhṛtyutsāhasamanvitaḥ|siddhyasiddhyornirvikāraḥ kartā sāttvika ucyate||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).