Bhagavad Gita · Chapter 4: Knowledge and the Renouncing of Action
Bhagavad Gita 4.20
त्यक्त्वा कर्मफलासङ्गं नित्यतृप्तो निराश्रयः ।
कर्मण्यभिप्रवृत्तोऽपि नैव किञ्चित्करोति सः ॥
tyaktvā karmaphalāsaṅgaṃ nityatṛpto nirāśrayaḥ | karmaṇyabhipravṛtto'pi naiva kiñcitkaroti saḥ ||
Having given up attachment to the fruit of action, always content and dependent on nothing, such a person does nothing at all, even while fully engaged in action.
Modern context
Two qualities are named: always content, and dependent on nothing. Most of us work in order to become content, and so our work carries the weight of that need. The person described here is already content and works from fullness. Such a person can be extremely active, and yet inwardly there is no straining, no 'I am doing this so that I may be happy'. In that sense, the verse says, they do nothing at all.