Bhagavad Gita · 3.17

यस्त्वात्मरतिरेव स्यादात्मतृप्तश्च मानवः।आत्मन्येव च सन्तुष्टस्तस्य कार्यं न विद्यते॥

yas tv ātma-ratir eva syād ātma-tṛptaśh cha mānavaḥ ātmany eva cha santuṣhṭas tasya kāryaṁ na vidyate

But one who rejoices in the Self alone, who is satisfied with the Self, and who is content in the Self — for such a person, there is no duty to perform.

— Bhagavad Gita 3.17

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)