All imposture weakens confidence and chills benevolence.
 Samuel Johnson, The History of Rasselas, Prince of Abissinia (1759). copy citation

Context

“but I have yet a stronger objection against the misrepresentation of your state. I have always considered it as treason against the great republic of human nature to make any man’s virtues the means of deceiving him, whether on great or little occasions. All imposture weakens confidence and chills benevolence. When the sage finds that you are not what you seemed, he will feel the resentment natural to a man who, conscious of great abilities, discovers that he has been tricked by understandings meaner than his own, and perhaps the distrust which he can never afterwards wholly lay aside may stop the voice of counsel and close the hand of charity;” source