Everything is created with a purpose, in order that we may use it for its purpose. And so it is with people. Sa'di says, "Every being is created for a purpose, and the light of that purpose is already kindled in his soul." As we need blacksmiths and goldsmiths and farmers and others, so we need philosophers and mystics and prophets. That creates the harmony, just as we need sharp and fiat in music. If it were not so there would be no beauty, for beauty is created through variety.