The philosopher is not a king. Politics is for the sake of philosophy. Moral activity is for the sake of scientific activity. Action is for the sake of contemplation. Motion is for the sake of rest.
Work is for the sake of leisure.
Happiness is the end of human beings. Happiness includes but is higher than justice. Happiness requires the fulfillment of specifically human tendencies or desires, the highest of which are social and scientific tendencies. The ruler can be relatively happy, but the philosopher can be supremely happy. Happiness requires wealth and good luck.