Krishna advised one to begin on the path toward selflessness by renouncing the fruits of one's labor (Text 20). Here, Krishna describes the advances stage one can eventually achieve by such practice of renunciation.
Nirashir yata cittatma tyaktva sarva parigrahah - Desirelessness and freedom from possessiveness
One can eventually attain a state wherein he is completely free from all attachment, not only to the fruits of work, but even to the work itself.
Shariram kevalam karma - Only the body acts
When such a great soul eats, sleeps, etc., his heart and mind are not absorbed in those activities. His body performs them dutifully, as if on auto pilot.