This is a quote from Siddhartha by Hermann Hesse.
The phrase NAM-MYOHO-RENGE-KYO is taken from the title of the greatest teaching of the first historically recorded Buddha, known as Siddhartha Gautama or Shakyamuni Buddha, who lived in India around 500 years before Christ was born. This teaching, called the Lotus Sutra, declares that all living beings, regardless of gender or intelligence (that means everyone – including you and me!), have the potential to attain Buddhahood. In the Lotus Sutra, Shakyamuni Buddha teaches that inside each one of us a universal truth known as the Buddha nature.