Bg 3.17

yas tv atma-ratir eva syad
atma-trptas ca manavah
atmany eva ca santustas
tasya karyam na vidyate

Word for word: 
yah — one who; tu — but; atma-ratih — taking pleasure in the Self; eva — certainly; syat — remains; atma-trptah — self-illuminated; ca — and; manavah — a man; atmani — in himself; eva — only; ca — and; santustah — perfectly satiated; tasya — his; karyam — duty; na — does not; vidyate — exist.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
But for one who takes pleasure in the Self, whose human life is one of self-realization, and who is satisfied in the Self only, fully satiated – for him there is no duty.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
A person who is fully Krishna conscious, and is fully satisfied by his acts in Krishna consciousness, no longer has any duty to perform. Due to his being Krishna conscious, all impiety within is instantly cleansed, an effect of many, many thousands of yajña performances. By such clearing of consciousness, one becomes fully confident of his eternal position in relationship with the Supreme. His duty thus becomes self-illuminated by the grace of the Lord, and therefore he no longer has any obligations to the Vedic injunctions. Such a Krishna conscious person is no longer interested in material activities and no longer takes pleasure in material arrangements like wine, women and similar infatuations.