Arjuna’s confusion is caused by the apparent irreconcilable differences between Sankhya, which focuses on renunciation of action in order to achieve liberation and Yoga, which looks to achieve liberation while undertaking works through an inner process of renunciation.
The first great synthesis of the Gita is to reconcile these two, and it does so by reframing the definition of “renunciation”. The physical act of renouncing action is not the essential point; rather, it is the inner state of detachment from action and its fruits that leads to true liberation.
Sri Aurobindo, quoting the Gita indicates: “Renunciation and Yoga of works both bring about the soul’s salvation, but of the two the Yoga of works is distinguished above the renunciation of works. He should be known as always a Sannyasin (even when he is doing action) who neither dislikes or desires; for free from the dualities he is released easily and happily from the bondage. Children speak of Sankhya and Yoga apart from each other, not the wise; if a man applies himself integrally to one, he gets the fruit of both…”
“But renunciation is difficult to attain without Yoga; the sage who has Yoga attains soon to the Brahman; his self becomes the self of all existences (of all things that have become), and even though he does works, he is not involved in them.”
“He knows that the actions are not his, but Nature’s and by that very knowledge he is free; he has renounced works, does no actions, though actions are done through him; he becomes the Self, the Brahman, brahmabhuta, he sees all existences as becomings (bhutani) of that self-existent Being, his own only one of them, all their actions as only the development of cosmic Nature working through their individual nature and his own actions also as a part of the same cosmic activity.”
Sri Aurobindo, Essays on the Gita, First Series, Chapter 9, Sankhya, Yoga and Vedanta, pp. 76-77,