त्यक्त्वा कर्मफलासङ्गं नित्यतृप्तो निराश्रयः। कर्मण्यभिप्रवृत्तोऽपि नैव किञ्चित्करोति सः ॥

tyaktvā karma-phalāsaṅgaṁ nitya-tṛipto nirāśhrayaḥ karmaṇyabhipravṛitto ’pi naiva kiñchit karoti saḥ

Having abandoned attachment to the fruit of action, always content, nowhere seeking refuge, he is not doing anything, although doing actions.

In plain words: Krishna says that a person who stops clinging to the results of his work stays content. He does not lean on anything outside himself for security. Even though he keeps working, it is as if he is not doing anything, because the work does not bind him.