Apart from action done as sacrifice, this world is bound by its own actions. So, O son of Kunti, perform action for the sake of sacrifice, free from attachment.
Explanation
Krishna is telling Arjuna that action cannot simply be abandoned, so the question is how to act without being bound. Sacrifice (yajña) here means action done as an offering or duty for a larger good, rather than for personal gain. Action done for self-interest binds a person (bandhana), while action done without attachment (saṅga) does not. Commentators differ on what yajña means: some take it as Vedic ritual, others as selfless duty or offering all work to God.