essence of Karma-yoga is selflessness, or the realisation that there is
no self-in the sense of ego-self or the doer and the enjoyer. The realisation
of the non-existence of the self is co-existent with the realisation that
'Brahman alone exists, there is no diversity'. When there is the direct
realisation of this truth there is utter selflessness. Action that flows
from that selflessness is Karma-yoga.
When one is established in self-realisation, Raga (attraction), Bhaya (fear)
and Krodha (hate) are completely absent. There is total non-attachment;
there is a complete absence of fear and hate. This is the fundamental definition
of a Karma yogi given in the Bhagavad-Gita.
Life flows on without Raga, Bhaya and Krodha, because there is no self to
get attached to something, to hate something, or to be afraid of something.
When one has reached that state of Yoga there is utter tranquility within.