A devotee has to learn to feel helpless while executing his duty. Why does a devotee perform a particular duty? He knows he must be dutiful in order to please guru and Krsna. Duty purifies us. We carry out so many self-imposed duties, thinking we must do them, but the greatest, most compelling duty is to offer whatever we are doing to Krsna.
Lectures From a Disciple, Vol 1, p. 242