B.G 4.18

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

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.

कर्मादिस्वरूपमाह - कर्मणीति।

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

कर्मणि क्रियमाणे सति अकर्म यः पश्येत् 'विष्णोरेव कर्म नाहं चित्प्रतिबिम्बः किञ्चित् करोमि' इति।

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.'

अकर्मणि सुप्त्यादौ अकरणावस्थायां परमेश्वरस्य कर्म यः पश्यति 'अयमेव परमेश्वरः सर्वदा सर्वसृष्ट्यादि करोति' इति।

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'.

स बुद्धिमान् ज्ञानी । स एव च युक्तो योगयुक्तः। सर्वाकरणात् स एव च कृत्स्नकर्मकृत् कृत्स्नफलत्वात् ॥१८॥

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.