"Karmanye Vadhikaraste Ma Phaleshu Kadachana"...
One of the best message in Bhagavadgeeta-
"Karmanye Vadhikaraste, Ma phaleshou kada chana,
Ma Karma Phala Hetur Bhurmatey Sangostva Akarmani"
You have a right to perform your prescribed duty, but you are not entitled to the Results of actions.
Do not consider yourself the cause of the results of your activities, and never be attached to not doing your duty.