In a gabled house the rafters all converge on the ridgepole, they are fixed on the ridgepole and join together there equally; in the same way, whatever wrong states of mind exist, they are all rooted in ignorance, fixed in ignorance and joined together there. Ignorance of good is the cause of wrongdoing. Therefore, you must live in mindfulness and train yourself in this.
- Samyutta Nikaya