Tamāla Kṛṣṇa: Seventeen: "One who is, however, taking pleasure in the self, who is illumined in the self, who rejoices in and is satisfied with the self only, fully satiated, for him there is no duty."
Prabhupāda: Here it is plainly said by Lord Kṛṣṇa, "the self, one who is taking pleasure in self." How we can take pleasure in self? As soon as we engage ourself with the Supreme Self. That is enjoyment. Ānandamayo 'bhyāsāt (Vedānta-sūtra 1.1.12). The Supreme Lord is joyful. Just like if you mix with a joyful society or joyful person, then automatically you become joyful. There is no necessity of becoming joyful separately. That association will make you joyful. If you mix with a society criminal, automatically you become criminal. There is no necessity of learning criminality separately.
By association, you'll do that. Similarly, if you associate with the supreme joyful, Kṛṣṇa, automatically you become joyful. This is Kṛṣṇa consciousness. Automatically. There is no necessity separately how to become joyful. Simply by association.
Therefore here it is said that, "One who rejoices in." That rejoice is by association with the Supreme. "And is satisfied with the self only." With self. My self, what I am? My identity is that I am eternal servant of God. So as soon as I engage myself in the service of God, that is my self-realization. And if I enjoy in that self-realization, then I have no other duty. Finished. I have finished all duty, all sacrifice, everything complete.