One whose mind is unattached everywhere, who has mastered the self and is free from craving, reaches through renunciation the supreme perfection of freedom from action.
Explanation
Krishna is explaining to Arjuna how a person can reach freedom from action (naiṣkarmya), the state in which action no longer binds, without simply abandoning action. The key is an unattached mind (asakta-buddhi), self-mastery and freedom from craving (spṛhā), and this inner renunciation (saṃnyāsa) brings the highest perfection. Traditions differ here: Advaita reads it as the fruit of knowledge-based renunciation, while others read it as renouncing attachment to results while still acting.