Bhagavad Gita Chapter 13, Verse 21

कार्यकारणकर्तृत्वे हेतुः प्रकृतिरुच्यते | पुरुषः सुखदुःखानां भोक्तृत्वे हेतुरुच्यते ||

kārya-kāraṇa-kartṛtve hetuḥ prakṛtir ucyate puruṣaḥ sukha-duḥkhānāṁ bhoktṛtve hetur ucyate

Material nature is said to be the cause of all actions and their effects. The enjoyer is said to be the cause of experiencing pleasure and pain.

Krishna explains the roles of prakriti (material nature, the field) and purusha (the enjoyer, the knower). 'Kārya-kāraṇa-kartṛtve hetuḥ prakṛtir ucyate'—material nature is the cause of all actions and their effects. The field is the doer—it performs actions, creates effects. 'Puruṣaḥ sukha-duḥkhānāṁ bhoktṛtve hetur ucyate'—the enjoyer is the cause of experiencing pleasure and pain. The knower is the experiencer—it experiences the field's actions and effects as pleasure and pain. This distinction is crucial: the field does, the knower experiences. The field is the agent of action, the knower is the experiencer of the results. When you understand this, you recognize that you (the knower) are not the doer—the field does. You are the experiencer—you experience the field's actions. This understanding liberates you from the burden of doership—you're not responsible for the field's actions, you're the witness of them.