Bhagavad Gita · Sankhya YogaChapter 2, Shloka 47 (2.47)

Four principles, one shloka. This shloka says four things:

1. Karmaṇy evādhikāras te — your right is to action.
2. Mā phaleṣu kadācana — never to the fruits.
3. Mā karma-phala-hetur bhūḥ — do not let the fruit be what drives your action.
4. Mā te saṅgo 'stv akarmaṇi — but do not be attached to giving up action either.

"Adhikāra" — what "right" means. Adhikara means — your domain, your responsibility, where you have control. The action is in your hands; the fruit depends on many factors (place, time, other people, nature). So to claim a "right" over the fruit is pointless worry and attachment.

Most important — the fourth part. People often remember the first half of the shloka and forget the last part: mā te saṅgo 'stv akarmaṇi — "do not be attached to not acting". Shankaracharya: if I do not want the fruit, then "why should I do action, which is painful?" — do not cherish such inaction (not acting). This is aimed straight at Arjuna: he had said "I do not want the fruit (the kingdom), so I will not fight" (1.32). Krishna says: give up desire for the fruit — not the action.

Three commentaries, three emphases:

• Shankaracharya: "Your right is to action alone — not to the discipline of knowledge" (that is, for someone like Arjuna, karma-yoga for now). There should be no thirst for the fruit in any situation; action done with thirst for the fruit becomes the cause of birth (rebirth).
• Ramanuja: The seeker of liberation has a right to action alone, not to its fruits — because action with its fruits is bondage, while action without fruit, as worship of the Lord, is the cause of moksha. At the same time — do not consider yourself the doer either; doership depends on the gunas and ultimately on the Lord of all.
• Madhva: "Te" (your) stands for more than itself — if even for a wise one like you action is not to be done out of desire for fruit, what of others? That is, this principle is for everyone.