Full Idea
Corruption afflicts the intellect because of falsehoods, and from such a mind there arise many passions and causes of instability.
Gist of Idea
Falsehoods corrupt a mind, producing passions and instability
Source
report of Stoic school (fragments/reports [c.200 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.110
A Reaction
In Dec 2017 this ancient wisdom perfectly fits the current President of the USA.
Book Reference
'The Stoics Reader', ed/tr. Inwood,B/Gerson,L.P. [Hackett 2008], p.119