B.G 4.18

कर्मण्यकर्म यः पश्येदकर्मणि च कर्म यः। स बुद्धिमान् मनुष्येषु स युक्तः कृत्स्नकर्मकृत् ॥१८॥

karmaṇyakarma yaḥ paśyedakarmaṇi ca karma yaḥ। sa buddhimān manuṣyeṣu sa yuktaḥ kr̥tsnakarmakr̥t ॥18॥

He who sees non-action in activities, and sees action in non-activities is the knowledgeable among humans, and he is rightly engaged in Yōga and performs all the right actions.

Gīta Bhāshya 4.18

The person who perceives non-action in action thinks, "Indeed, I am only reflecting what is presented to my consciousness. Vishnu is the one who is performing the actions, not me." Person who perceives action in non-action thinks - 'This indeed is the Supreme Lord who always performs activities such as creation and so on'. 'buddhimān' - knowledgeable. 'yukto' - engaged in Yōga. 'kr̥tsnakarmakr̥' - indicates he alone gets all-encompassing results.

The verse 'karmaṇi' describes the essence and nature of action.

When action is being performed, one who perceives non-action, thinks - 'Indeed, Vishnu only is doing the actions, not I. I am only reflecting what my consciousness presents to me.'

When in the state of non-action such as sleep and so on, one who perceives the actions of the Supreme Lord, thinks - 'This indeed is the Supreme Lord who always performs activities such as creation and so on'.

He is 'buddhimān', means he is knowledgeable. Such a person only is 'yukta', means he is engaged in Yōga. Because of absence of all self driven actions, such a person alone is 'kr̥tsnakarmakr̥', i.e. performs all right actions, which means, he alone gets all-encompassing results.