Bhagavad Gita Chapter 18, Verse 17

यस्य नाहंकृतो भावो बुद्धिर्यस्य न लिप्यते | हत्वापि स इमाँल्लोकान्न हन्ति न निबध्यते ||

yasya nāhaṅkṛto bhāvo buddhir yasya na lipyate hatvāpi sa imāṁl lokān na hanti na nibadhyate

One whose nature is not ego-based, whose intellect is not tainted, even having killed these beings, does not kill, nor is bound.

Krishna describes sattvic action through the example of Arjuna's situation. 'Yasya nāhaṅkṛto bhāvaḥ'—one whose nature (bhāvaḥ) is not ego-based (na ahaṅkṛtaḥ). 'Buddhir yasya na lipyate'—whose intellect (buddhiḥ) is not tainted (na lipyate) by attachment. 'Hatvāpi sa imāṁl lokān na hanti na nibadhyate'—even having killed (hatvā api) these beings (imāṁl lokān), does not kill (na hanti), nor is bound (na nibadhyate). This is the key teaching about sattvic action: when you act without ego and without attachment, you're not bound by the action. Arjuna's duty is to fight, but if he does it without ego and without attachment, he's not bound by the consequences. This is sattvic action: performing duty without ego-based nature and without tainted intellect. The action itself may seem the same (killing in battle), but the quality of the action (ego-less, unattached) determines whether it binds you.