Isadore of Seville

Without music no discipline can be perfect, for there is nothing without it. For the very universe is held together by a certain harmony of sounds, and the heavens themselves are made to revolve by the modulation of harmony. Music moves the feelings and changes the emotions... The very beasts also, even serpents, birds, and dolphins, music incites to listen to her melody. And every word we speak, every pulsation in our veins, is related by musical rhythms to the powers of harmony.