Those who speak falsehoods end up injuring many

 Men who do wrong and speak falsehood ought to disparage as well all other good things. For there will be found also among men who possess these qualities some who do wrong and use these advantages to the injury of many. Isocrates.  Nicocles or the Cyprians.  Speech 3.  Section 3.

Image: The Great Fire of Rome by the late British illustrator John E. McConnell.