 
                            
                        
                        
                        The Notebooks of Leonardo da Vinci (1883), I Prolegomena and General Introduction to the Book on Painting
The Notebooks of Leonardo da Vinci (1883), I Prolegomena and General Introduction to the Book on Painting
                                        
                                        The Notebooks of Leonardo da Vinci (1883), XIX Philosophical Maxims. Morals. Polemics and Speculations. 
Variant: Just as iron rusts from disuse... even so does inaction spoil the intellect.
                                    
“As iron is eaten away by rust, so the envious are consumed by their own passion.”
                                        
                                        § 5 
From Lives and Opinions of the Eminent Philosophers by Diogenes Laërtius
                                    
Source: Treatise Concerning Eternal and Immutable Morality (1731), Ch. 1, sct. 1
                                        
                                        Irshadul Qulub; Page 78 
Shi'ite Hadith
                                    
“Lies are rust on iron. A blemish on power.”
Source: Golden Son (2015), Ch. 15: Truth; Aja
 
                            
                        
                        
                         
                            
                        
                        
                         
                            
                        
                        
                        