For it is a natural consequence when wickedness abounds within, that wicked words are breathed as far as the mouth; and therefore when you hear of a man uttering abominable things, do not suppose that there lies only so much wickedness in him as is expressed in his words, but believe the fountain to be more copious than the stream.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. 42. in Matt.