A very good talk about an ancient and powerful idea:
कर्मण्येवाधिकारस्ते मा फलेषु कदाचन
मा कर्मफलहेतुर्भूर्मा ते संगोस्त्वकर्मणि
Translation from The Holy Geetha, Commentary by Swami Chinmayananda:
"Thy right is to work only, but never to its fruits; let not the fruit-of-action be thy motive, nor let thy attachment be to inaction."