"How do you know all this?" he cried. "Are you a devil?"
"I am a man," answered Father Brown gravely; "and therefore have all devils in my heart."
- G. K. Chesterton, The Hammer of God
The heart is deceitful above all things,
And desperately wicked.
- Jeremiah 17:9
For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, thefts, covetousness, wickedness, deceit, lewdness, an evil eye, blasphemy, pride, foolishness. All these evil things come from within and defile a man.
- Mark 7:21-23