We consider a prisoner unfortunate. He is unfortunate in two ways — because he has done something wrong and because he is deprived of his liberty. Therefore we should treat him kindly, because of his misfortune, for otherwise he would become hard and bitter and would not be sorry he had done wrong. Ozma thinks that one who has committed a fault did so because he was not strong and brave; therefore she puts him in prison to make him strong and brave. When that is accomplished he is no longer a prisoner, but a good and loyal citizen and everyone is glad that he is now strong enough to resist doing wrong. You see, it is kindness that makes one strong and brave; and so we are kind to our prisoners.

The Patchwork Girl of Oz - Later Oz novels