tatraivaṃ sati kartāramātmānaṃ kevalaṃ tu yaḥ |paśyatyakṛtabuddhitvānna sa paśyati durmatiḥ ||
That being so, one who sees himself alone as the doer, because his understanding is untrained, does not see things as they are; he is of poor judgment.
Explanation
Krishna has just listed five factors behind any action (the body, the doer, the instruments, the efforts and the divine or fate factor). Here he says that someone who sees himself (ātman) as the only doer has an untrained understanding (akṛta-buddhi) and misses the full picture. Traditions differ on the emphasis: Advaita readings stress that the pure Self does not act at all, while devotional readings stress that God is among the causes.