What they call renunciation (sannyasa), know that to be yoga, O son of Pandu. For no one becomes a yogi without giving up the resolves of the mind.
Explanation
Krishna continues speaking to Arjuna, building on the previous verse, which said that one who acts without clinging to results is both a renouncer and a yogi. Here he says renunciation (saṃnyāsa) and discipline of action (yoga) are at heart the same. Either way, the key is letting go of selfish plans and desires (saṅkalpa), the mental projecting of wants and outcomes.