גרת הרמב”ן

This letter was sent by the Ramban from his city to his son in Catalonia, regarding the act humility. And instructed him to read this once every week and to teach it to others as well, and to learn it by heart, in order to train them in their youth to fear Heaven. The Ramban assured him that on the day that he read this letter his wishes would be fulfilled from heaven. And whoever will accustom themselves to saying it will spare themselves from all pains and they are assured to inherit the world to come. (From the Sefer Me’ulephet Sappirim.)