Bhagavad Gita · Chapter 18: Freedom through Renunciation
Bhagavad Gita 18.26
मुक्तसङ्गोऽनहंवादी धृत्युत्साहसमन्वितः ।
सिद्ध्यसिद्ध्योर्निर्विकारः कर्ता सात्त्विक उच्यते ॥
muktasaṅgo'nahaṃvādī dhṛtyutsāhasamanvitaḥ | siddhyasiddhyornirvikāraḥ kartā sāttvika ucyate ||
A doer who is free from attachment, who does not talk of "I," who is full of resolve and enthusiasm, and who is unchanged by success or failure, is said to be of clarity.
Modern context
The sattvic doer is free of attachment, does not boast, is full of resolve and enthusiasm, and is unchanged by success or failure. Notice that enthusiasm is included. The ideal worker is not detached in the sense of being indifferent. They are energetic and committed, but their energy does not depend on winning. That combination, wholehearted and unattached, is the Gita's picture of the best kind of worker.